4 Perioden Zentriert Gleitender Durchschnitt

Präzession der Äquinoktien In der Astronomie ist die axiale Präzession eine schwerkraftinduzierte, langsame und kontinuierliche Veränderung der Orientierung einer astronomischen Rotationsachse. Sie bezieht sich insbesondere auf die allmähliche Verschiebung der Orientierung der Rotationsachse der Erde, die wie eine wackelnde Oberseite ein Paar Kegel spürt, die an ihren Spitzen in einem Zyklus von ungefähr 26.000 Jahren (genannt ein großes oder platonisches Jahr in Astrologie). Der Begriff Präzession bezieht sich in der Regel nur auf diese größte säkulare Bewegung andere Änderungen in der Ausrichtung der Erde Achse - Nutation und polare Bewegung - sind viel kleiner in der Größe. Die Erdpräzession wurde historisch als Präzession der Äquinoktien bezeichnet, weil die Äquinoktien nach Westen entlang der Ekliptik relativ zu den festen Sternen entgegengesetzt zur Bewegung der Sonne entlang der Ekliptik wanderten. Dieser Begriff wird immer noch in nicht-technischen Diskussionen verwendet, dh wenn detaillierte Mathematik nicht vorhanden ist. Historisch gesehen, ist Hipparchus mit der Entdeckung Präzession der Tagundnachtgleiche gutgeschrieben. Die genauen Daten seines Lebens sind nicht bekannt, aber astronomische Beobachtungen, die ihm von Ptolemäus zugeschrieben wurden, datieren von 147 v. Chr. Bis 127 v. Chr. Mit Verbesserungen in der Fähigkeit, die Gravitationskraft zwischen Planeten während der ersten Hälfte des 19. Jahrhunderts zu berechnen, wurde erkannt, dass sich die Ekliptik selbst leicht bewegte, die bereits 1863 als planetarische Präzession bezeichnet wurde, während die dominante Komponente lunisolare Präzession genannt wurde. Ihre Kombination wurde genannt allgemeine Präzession statt Präzession der Äquinoktien. Die lunisolare Präzession wird durch die Gravitationskräfte des Mondes und der Sonne auf der äquatorialen Ausbuchtung der Erde verursacht, wodurch die Erdachse in Bezug auf den Trägheitsraum bewegt wird. Planetarische Präzession (eigentlich ein Fortschritt) ist auf den kleinen Winkel zwischen der Gravitationskraft der anderen Planeten auf der Erde und ihrer Bahnebene (der Ekliptik) zurückzuführen, was dazu führt, dass sich die Ebene der Ekliptik geringfügig gegenüber dem Trägheitsraum verschiebt. Die lunisolare Präzession ist etwa 500 mal größer als die planetarische Präzession. Neben dem Mond und der Sonne verursachen die anderen Planeten auch eine kleine Bewegung der Erdachse im Trägheitsraum, was den Kontrast zu den Begriffen lunisolar und planetarischer Irreführung macht. Daher empfahl die Internationale Astronomische Union im Jahr 2006, die dominante Komponente in die Präzession umzubenennen Des Äquators und der Nebenkomponente in Präzession der Ekliptik umbenannt, aber ihre Kombination wird noch als allgemeine Präzession bezeichnet. Die Präzession der Äquinoktien wird durch die Gravitationskräfte der Sonne und des Mondes und in geringerem Maße auch anderer Körper auf der Erde verursacht. Es wurde zuerst von Sir Isaac Newton erklärt. Axiale Präzession ist ähnlich der Präzession eines Spinnkopfes. In beiden Fällen ist die angelegte Kraft auf die Schwerkraft zurückzuführen. Für eine Spinnspitze neigt diese Kraft nahezu parallel zur Rotationsachse. Für die Erde jedoch sind die angelegten Kräfte der Sonne und des Mondes nahezu senkrecht zur Rotationsachse. Die Erde ist nicht eine vollkommene Sphäre, sondern eine schräge Sphäroid mit einem Äquatorialdurchmesser von etwa 43 Kilometern größer als ihr polarer Durchmesser. Wegen der axialen Kippung der Erde ist die Hälfte dieser Beule, die der Sonne am nächsten liegt, außerhalb des Zentrums, entweder im Norden oder im Süden, und die ferne Hälfte ist auf der gegenüberliegenden Seite außermittig. Der Gravitationszug auf der engeren Hälfte ist stärker, da die Schwerkraft mit der Entfernung abnimmt, so dass dies ein kleines Drehmoment auf der Erde erzeugt, während die Sonne auf einer Seite der Erde härter als die andere härtet. Die Achse dieses Drehmomentes ist ungefähr senkrecht zur Achse der Erddrehung, so daß die Drehachse vorangeht. Wenn die Erde eine perfekte Sphäre wäre, gäbe es keine Präzession. Dieses mittlere Drehmoment ist senkrecht zu der Richtung, in der die Drehachse von dem Ekliptikpol weg gekippt wird, so daß sie die axiale Neigung selbst nicht verändert. Die Größe des Drehmoments von der Sonne (oder dem Mond) variiert mit der Ausrichtung der Gravitationsobjekte zur Erddrehachse und nähert sich null, wenn sie orthogonal ist. Obwohl die obige Erklärung die Sonne betrifft, gilt dieselbe Erklärung für alle Objekte, die sich um die Erde, entlang oder in der Nähe der Ekliptik, insbesondere des Mondes, bewegen. Die kombinierte Aktion der Sonne und des Mondes wird die lunisolare Präzession genannt. Zusätzlich zu der stetigen progressiven Bewegung (die in einem Vollkreis in etwa 25.700 Jahren resultiert) verursachen die Sonne und der Mond auch kleine periodische Schwankungen aufgrund ihrer wechselnden Positionen. Diese Oszillationen sind sowohl in der Präzessionsgeschwindigkeit als auch in der Axialkippung als die Nutation bekannt. Der wichtigste Begriff hat eine Periode von 18,6 Jahren und eine Amplitude von weniger als 20 Sekunden des Bogens. Zusätzlich zur lunisolaren Präzession bewirken die Aktionen der anderen Planeten des Sonnensystems, dass sich die gesamte Ekliptik langsam um eine Achse dreht, die eine ekliptische Länge von etwa 174 aufweist, die auf der augenblicklichen Ekliptik gemessen wird. Diese sogenannte planetare Präzessionsverschiebung beträgt eine Drehung der ekliptischen Ebene von 0,47 Sekunden Bogen pro Jahr (mehr als hundertmal kleiner als die lunisolare Präzession). Die Summe der beiden Präzessionen wird als allgemeine Präzession bezeichnet. Die Präzession der Erdachse hat eine Reihe von beobachtbaren Effekten. Zuerst scheinen sich die Positionen der südlichen und nördlichen himmlischen Pole im Kreise gegen den raumfesten Hintergrund der Sterne zu bewegen, was einen Kreislauf in 25.772 Julianischen Jahren (2000er Rate) vollendet. So, während heute der Stern Polaris etwa auf dem nördlichen himmlischen Pole liegt, wird dies im Laufe der Zeit ändern, und andere Sterne werden die Nord-Sterne werden. Der südliche Himmelsstab fehlt derzeit ein heller Stern, um seine Position zu markieren, aber im Laufe der Zeit wird die Präzession auch dazu führen, dass helle Sterne zu Südsterne werden. Wenn sich die Himmelspole verschieben, gibt es eine entsprechende allmähliche Verschiebung in der scheinbaren Orientierung des ganzen Sternfeldes, gesehen von einer bestimmten Position auf der Erde. Zweitens ändert sich die Lage der Erde in ihrer Umlaufbahn um die Sonne an den Solstiteln, Äquinoktien oder anderen Zeitpunkten relativ zu den Jahreszeiten. Nehmen wir zum Beispiel an, dass die Erdorbitalposition an der Sommersonnenwende markiert ist, wenn die Erd-Axialkippung direkt auf die Sonne zeigt. Eine volle Umlaufbahn später, wenn die Sonne zu der gleichen scheinbaren Position relativ zu den Hintergrundsternen zurückgekehrt ist, ist die Erd-Axialkippung jetzt nicht direkt zur Sonne hin: Wegen der Auswirkungen der Präzession ist sie ein wenig weit darüber hinaus. Mit anderen Worten, die Sonnenwende trat etwas früher in der Umlaufbahn auf. So ist das tropische Jahr, das den Zyklus der Jahreszeiten misst (z. B. die Zeit vom Sonnenwende bis zum Sonnenwende oder Äquinoktium bis zum Äquinoktium), etwa 20 Minuten kürzer als das siderische Jahr, das durch die scheinbare Position der Sonne gegenüber den Sternen gemessen wird . Beachten Sie, dass 20 Minuten pro Jahr ungefähr ein Jahr pro 25.772 Jahre entspricht, also nach einem vollen Zyklus von 25.772 Jahren die Positionen der Jahreszeiten in Bezug auf die Umlaufbahn zurück sind, wo sie begannen. (In Wirklichkeit ändern andere Effekte auch langsam die Form und Orientierung der Erdumlaufbahn, und diese erzeugen in Kombination mit der Präzession verschiedene Zyklen unterschiedlicher Perioden, siehe auch Milankovitch-Zyklen. Die Größe der Erde neigt sich im Gegensatz zur bloßen Orientierung , Ändert sich aber im Laufe der Zeit langsam, aber dieser Effekt wird nicht direkt der Präzession zugeschrieben.) Aus identischen Gründen rückt die scheinbare Position der Sonne relativ zur Kulisse der Sterne zu einer saisonal festgelegten Zeit, so die Frühjahrsgleiche, langsam zurück 360 durch alle zwölf traditionellen Sternbilder des Tierkreises, mit einer Geschwindigkeit von ungefähr 50.3 Sekunden Bogen pro Jahr (ungefähr 360 Grad geteilt durch 25.772) oder 1 Grad alle 71.6 Jahre. Alter des Wassermanns Wir sind angeblich im Zeitalter des Wassermanns. Nach astrologischer Mystik wird es ungewöhnliche Harmonie und Verständnis in der Welt geben. Diejenigen, die diesem Glaubenssystem folgen, sehen es als Wendepunkt im menschlichen Bewusstsein, in dem das Gleichgewicht wiederhergestellt wird, indem es bewusst über den physischen Körper hinausgeht. Das Symbol des Wassermannes ist inhaltlich metaphorisch - dh Verschluss im Wasser. Wasser repräsentiert das kollektive Bewusstseins - oder Bewusstseinshologramm, das die Gitterprogramme unserer physischen Realität schafft. Viele verbinden das Zeitalter des Wassermanns mit der Rückkehr der Göttin, der Priesterin oder der femininen Energien - diejenigen, die über der physikalischen Frequenz vibrieren. Dies ist die Rückkehr zum höheren Bewusstsein, das Erwachen von höherem Geist und Denken in der Alchemie der Zeit. Das Zeitalter des Wassermanns ist das polare Gegenteil des Zeitalters des Leos - in der bipolaren Realität, in der wir das physikalische Experiment der Zeit und der Illusion durch die Bewusstseinsprojektion des Auges oder All Sehaugen erleben. Alter von Leo - ungefähr 13.000 Jahre später - Alter des Wassermanns Obwohl es noch-umstrittene Beweise gibt, dass Aristarchus von Samos bestimmte Werte für die sidereal und tropischen Jahre schon c. 280 v. Chr. Wird die Entdeckung der Präzession gewöhnlich Hipparchus (190-120 v. Chr.) Von Rhodos oder Nicaea, einem griechischen Astronomen, zugeschrieben. Nach Ptolemys Almagest, gemessen Hipparchus die Länge von Spica und anderen hellen Sternen. Vergleicht man seine Messungen mit Daten von seinen Vorgängern, Timocharis (320-260 v. Chr.) Und Aristillus (280 v. Chr.), Kam er zu dem Schluss, dass Spica 2deg gegenüber der herbstlichen Tagundnachtgleiche bewegt hatte. Er verglich auch die Längen des tropischen Jahres (die Zeit, die die Sonne braucht, um zu einer Tagundnachtgleiche zurückzukehren) und das siderische Jahr (die Zeit, die die Sonne braucht, um zu einem festen Stern zurückzukehren) und fand eine leichte Diskrepanz. Hipparchus gelangte zu dem Schluss, dass die Äquinoktien durch den Tierkreis in Bewegung waren (Präzessionen), und dass die Präzessionsrate nicht weniger als 1 Deg in einem Jahrhundert betrug, also ein vollständiger Zyklus in nicht mehr als 36000 Jahren abgeschlossen war. Praktisch alle Hipparchus-Schriften sind verloren, einschließlich seiner Arbeit über Präzession. Sie werden von Ptolemäus erwähnt, der die Präzession als die Rotation der Himmelssphäre um eine bewegungslose Erde erklärt. Es ist vernünftig anzunehmen, daß Hipparchos, wie der Ptolemäus, in geozentrischen Begriffen die Präzession als eine Bewegung des Himmels betrachtete. Der erste Astronom, von dem bekannt ist, dass er die Hipparchus-Arbeit an der Präzession fortgeführt hat, ist Ptolemäus im 2. Jahrhundert. Ptolemäus maß die Längengrade von Regulus, Spica und anderen hellen Sternen mit einer Variation der Hipparchus-Mondmethode, die keine Eklipsen erforderte. Vor dem Sonnenuntergang maß er den Längsbogen, der den Mond von der Sonne trennte. Dann, nach Sonnenuntergang, maß er den Bogen vom Mond zum Stern. Er benutzte das Hipparchus-Modell, um die Sonnenlängen zu berechnen und Korrekturen für die Mondbewegung und ihre Parallaxe vorzunehmen (Evans 1998, S. 251-255). Ptolemäus verglich seine eigenen Beobachtungen mit denen von Hipparchus, Menelaus von Alexandria, Timocharis und Agrippa. Er fand, dass zwischen Hipparchus Zeit und seine eigenen (etwa 265 Jahre), die Sterne 2 deg40 oder 1 deg in 100 Jahren (36 pro Jahr die Rate akzeptiert hat heute ist etwa 50 pro Jahr oder 1deg in 72 Jahren) bewegt. Er bestätigte auch, dass die Präzession alle festen Sterne, nicht nur die in der Nähe der Ekliptik betroffen, und sein Zyklus hatte gleichen Zeitraum von 36000 Jahren, wie von Hipparchus gefunden. Die meisten alten Autoren haben nicht erwähnt Präzession und vielleicht nicht wissen. Neben Ptolemäus enthält die Liste Proclus, der die Präzession verwarf, und Theon von Alexandria, ein Ptolemäer-Kommentator im 4. Jahrhundert, der die Erklärung von Ptolemys akzeptierte. Theon berichtet auch eine alternative Theorie: Nach gewissen Ansichten glauben alte Astrologen, dass aus einer bestimmten Epoche die solstitialen Zeichen eine Bewegung von 8deg in der Reihenfolge der Zeichen haben, wonach sie die gleiche Menge zurückgehen. (Dreyer 1958, S. 204) Statt durch die ganze Sequenz des Tierkreises zu gehen, zogen die Tagundnachtgleiche über einen Bogen von 8deg hin und her. Die Theorie der Trepidation wird von Theon als eine Alternative zur Präzession dargestellt. Alternative Theorien Verschiedene Behauptungen wurden gemacht, dass andere Kulturen die Präzession unabhängig von Hipparchus entdeckt haben. An einem Punkt wurde vorgeschlagen, dass die Babylonier über Präzession wissen konnten. Nach Al-Battani hatten die chaldäischen Astronomen das tropische und siderische Jahr ausgezeichnet (der Wert der Präzession entspricht dem Unterschied zwischen den tropischen und siderischen Jahren). Er erklärte, dass sie um 330 v. Chr. Eine Schätzung für die Länge des siderischen Jahres zu SK 365 Tage 6 Stunden 11 min (365,258 Tage) mit einem Fehler von (ca.) 2 min. Es wurde von P. Schnabel im Jahre 1923 behauptet, dass Kidinnu über Präzession in 315 v. Chr. Theoretisiert. Otto Neugebauers Arbeit zu diesem Thema in den 1950er Jahren ersetzte Schnabels (und früher, Kuglers) Theorie eines babylonischen Entdecker der Präzession. In den letzten Jahrzehnten wurde die Hypothese wiederbelebt und verstärkt in Santillana und von Dechends Hamlets Mill (Harvard University Press, 1969). In einer Anwendung des extremen Panbabylonismus auf die Archäoastronomie schlugen sie vor, dass eine babylonische mythologische Darstellung der Präzession durch Diffusion zu ähnlichen Mythen auf der ganzen Welt, auch so weit entfernt wie China, Polynesien und Nordamerika, entstand. Während ihre Theorie in der Akademie nicht allgemein akzeptiert wurde, erwartete sie die jüngste populäre Wiederbelebung des Interesses an der Präzessionsarchäoostronomie. Ähnliche Forderungen wurden gemacht, dass Präzession im alten Ägypten vor der Zeit von Hipparchus bekannt war, aber diese bleiben umstritten. Einige Gebäude in der Karnak-Tempel-Komplex, zum Beispiel wurden angeblich auf den Punkt am Horizont, wo bestimmte Sterne stieg oder zu den wichtigsten Zeiten des Jahres. Einige Jahrhunderte später, als die Präzession die Orientierungen veraltete, wurden die Tempel wieder aufgebaut. Allerdings bedeutet die Beobachtung, dass eine stellaren Ausrichtung falsch gewachsen ist nicht, dass die Ägypter verstanden, dass die Sterne über den Himmel bewegt in der Höhe von etwa einem Grad pro 72 Jahre. Dennoch hielten sie genaue Kalender und wenn sie das Datum der Tempelrekonstruktionen aufzeichneten, wäre es eine ziemlich einfache Sache, die grobe Präzessionsrate darzustellen. Der Dendera-Tierkreis, eine Sternkarte aus dem Hathor-Tempel in Dendera aus einem späten (ptolemäischen) Zeitalter, vermutet angeblich die Präzession der Äquinoktien (Tompkins 1971). In jedem Fall, wenn die alten Ägypter von Präzession wussten, wird ihr Wissen nicht in überlebenden astronomischen Texten aufgezeichnet. Michael Rice schrieb in seinem Egypts Legacy, Ob die Alten von der Mechanik der Präzession wussten oder nicht, bevor ihre Definition von Hipparchos die Bithynian im zweiten Jahrhundert v. Chr. Ist unsicher, aber als engagierte Beobachter des Nachthimmels konnten sie nicht bewusst sein Auswirkungen. (S. 128) Rice glaubt, dass die Präzession für das Verständnis dessen, was die Entwicklung Ägyptens antrieb, von grundlegender Bedeutung ist (S. 10), in einem Ausmaß, in dem Ägypten als Nationalstaat und der König von Ägypten als lebendiger Gott Sind die Produkte der Verwirklichung der astronomischen Veränderungen durch die Ägypter, die durch die immense scheinbare Bewegung der Himmelskörper, die die Precession impliziert, bewirkt werden. (S. 56) Nach Carl Jung sagt Rice, dass der Beweis, dass die am meisten verfeinerte astronomische Beobachtung in Ägypten im dritten Jahrtausend v. Chr. (Und wahrscheinlich auch vor diesem Zeitpunkt) praktiziert wurde, aus der Präzision der Pyramiden in Gizeh deutlich wird Zu den Himmelsrichtungen, eine Präzision, die nur durch ihre Ausrichtung mit den Sternen erreicht werden konnte. Diese Tatsache allein macht Jungs Glauben an die Ägypter Kenntnis der Precession viel weniger spekulativ als einmal es schien. (S. 31) Die Ägypter, so sagt Rice, sollten die Orientierung eines Tempels ändern, wenn der Stern, auf dessen Position er ursprünglich gesetzt war, seine Position als Folge der Precession bewegte, was während der Zeit mehrmals geschehen zu sein scheint Das neue Reich. (S. 170) Die Vorstellung, dass eine antike ägyptische Priester-Elite den Präzessionszyklus über viele Tausende von Jahren verfolgte, spielt eine zentrale Rolle in den von Robert Bauval und Graham Hancock in ihrem 1996er Buch Keeper of Genesis erläuterten Theorien. Die Autoren behaupten, dass die antiken Ägypter monumentale Bauvorhaben als eine Karte der Himmel fungierten, und dass damit verbundene Rituale eine aufwendige irdische Handlung aus himmlischen Ereignissen waren. Insbesondere symbolisierten die Rituale die Umkehr des Präzessionszyklus zu einer entfernten Ahnenzeit, die als Zep Tepi bekannt ist (erste Zeit), die, wie die Autoren berechnen, etwa 10.500 v. Chr. Es gibt Spekulationen, dass der Mesoamerican Long Count-Kalender irgendwie gegenüber der Präzession kalibriert ist, aber diese Ansicht wird nicht von professionellen Gelehrten der Maya-Zivilisation gehalten. Ein 12. Jahrhundert Text von Bhaskara II sagt: Sampat dreht sich negativ 30000 Mal in einem Kalpa von 4320 Millionen Jahren nach Suryasiddhanta, während Munjala und andere sagen, Ayana bewegt sich 199669 in einem Kalpa, und man sollte die beiden kombinieren, bevor die Feststellung der Declension, Ascension Unterschied, etc. Lancelot Wilkinson übersetzte die letzten dieser drei Verse in einer zu kurzen Weise, um die volle Bedeutung zu vermitteln, und übersprungen den Teil kombinieren die beiden, die die modernen Hindi-Kommentar in den Vordergrund gebracht hat. Nach der Hindi-Kommentar, sollte der endgültige Wert der Periode der Präzession durch die Kombination von 199669 Revolutionen von Ayana mit -30000 Umdrehungen von Sampaat zu erhalten 169669 pro Kalpa, dh eine Umdrehung in 25461 Jahren, die in der Nähe der modernen Wert von 25771 Jahren ist zu erhalten . Darüber hinaus gibt Munjalas Wert eine Periode von 21636 Jahren für Ayanas-Bewegung, die der moderne Wert der Präzession ist, wenn anomalistische Präzession auch berücksichtigt wird. Letztere hat eine Zeit von 136000 Jahren, aber Bhaskar-II gibt seinen Wert auf 144000 Jahre (30000 in einem Kalpa), nannte es sampan. Bhaskar-II gab keinen Namen des letzten Begriffs nach der Kombination der negativen Sampan mit dem positiven Ayana. Aber der Wert, den er gab, deutet an, daß er durch Ayana Präzession bedeutete wegen des kombinierten Einflusses von orbitalen und anomalistischen Präzessionen, und durch Sampan bedeutete er die anomalistische Periode, definierte sie aber als Äquinoktium. Seine Sprache ist ein wenig verwirrt, die er in seinem eigenen Vasanabhashya-Kommentar Siddhanta Shiromaniby erklärte, dass Suryasiddhanta nicht verfügbar war, und er schrieb auf der Grundlage von Hörensagen. Bhaskar-II gab nicht seine eigene Meinung, er zitierte nur Suryasiddhanta, Munjala und unbenannte andere. Yu Xi (4. Jh.) War der erste chinesische Astronom, der die Präzession erwähnte. Er schätzte die Rate der Präzession als 1deg in 50 Jahren (Pannekoek 1961, S. 92). Mittelalter und Renaissance In der mittelalterlichen islamischen Astronomie stellten die im Maragheh-Observatorium erstellten Zij-i Ilkhani die Präzession der Äquinoktien bei 51 Bogensekunden pro Jahr ein, die dem modernen Wert von 50,2 Bogensekunden sehr nahe kommt. Im Mittelalter behandelten islamische und lateinamerikanische Astronomen die Trepidation als eine Bewegung der festen Sterne, die der Präzession hinzugefügt werden sollten. Diese Theorie wird allgemein dem arabischen Astronomen Thabit ibn Qurra zugeschrieben, aber die Zuordnung ist in der modernen Zeit bestritten worden. Nicolaus Copernicus veröffentlichte in De revolutionibus orbium coelestium (1543) eine andere Darstellung der Trepidierung. Diese Arbeit macht den ersten definitiven Bezug zur Präzession als Ergebnis einer Bewegung der Erdachse. Kopernikus präzedierte die dritte Bewegung der Erde. Moderner Tag Über ein Jahrhundert später wurde die Präzession in Isaac Newtons Philosophiae Naturalis Principia Mathematica (1687) als eine Konsequenz der Gravitation erklärt (Evans 1998, S. 246). Allerdings nicht Newton ursprünglichen Präzession Gleichungen nicht funktionieren und wurden erheblich von Jean le Rond dAlembert und nachfolgende Wissenschaftler überarbeitet. Hipparchus Discovery Hipparchus berichtete über seine Entdeckung in der Verschiebung der Solstival - und Equinoctial-Punkte (beschrieben in Almagest III.1 und VII.2). Er maß die ekliptische Länge des Sterns Spica während der Mondfinsternisse und stellte fest, dass es etwa 6 Grad westlich der herbstlichen Tagundnachtgleiche war. Durch Vergleich seiner eigenen Messungen mit denen von Timocharis von Alexandria (ein Zeitgenosse von Euklid, der mit Aristillus früh im 3. Jahrhundert v. Chr. Arbeitete), fand er, dass Spicas Längengrad um ungefähr 2deg in ungefähr 150 Jahren verringert hatte. Er bemerkte auch diese Bewegung in anderen Sternen. Er spekuliert, dass nur die Sterne in der Nähe des Tierkreises im Laufe der Zeit verschoben. Ptolemäus nannte dies seine erste Hypothese (Almagest VII. 1), berichtete aber keine spätere Hypothese, die Hipparchus hätte entwickeln können. Hipparchus scheinbar beschränkt seine Spekulationen, weil er nur ein paar ältere Beobachtungen, die nicht sehr zuverlässig waren. Warum brauchte Hipparchus eine Mondfinsternis, um die Position eines Sterns zu messen Die äquinoktialen Punkte sind nicht am Himmel markiert, also brauchte er den Mond als Bezugspunkt. Hipparchus hatte bereits einen Weg gefunden, um die Länge der Sonne jeden Augenblick zu berechnen. Eine Mondfinsternis geschieht während des Vollmondes, wenn der Mond in der Opposition ist. Am Mittelpunkt der Sonnenfinsternis, ist der Mond genau 180deg von der Sonne. Hipparchus soll den Längsbogen gemessen haben, der Spica vom Mond trennt. Zu diesem Wert fügte er die berechnete Länge der Sonne hinzu, plus 180deg für die Länge des Mondes. Er tat das gleiche Verfahren mit Timocharis-Daten (Evans 1998, S. 251). Beobachtungen wie diese Finsternisse sind übrigens die Hauptdatenquelle, wann Hipparchus arbeitete, da andere biographische Informationen über ihn minimal sind. Die Mondfinsternisse beobachtete er zum Beispiel am 21. April 146 v. Chr. Und am 21. März 135 v. Chr. (Toomer 1984, S. 135 n. 14). Hipparchus studierte auch Präzession in über die Länge des Jahres. Zwei Arten von Jahr sind relevant für das Verständnis seiner Arbeit. Das tropische Jahr ist die Zeitspanne, in der die Sonne, von der Erde aus gesehen, die gleiche Position entlang der Ekliptik (ihren Weg unter den Sternen auf der himmlischen Sphäre) annimmt. Das siderische Jahr ist die Länge der Zeit, die die Sonne nimmt, um zu der gleichen Position in Bezug auf die Sterne der himmlischen Sphäre zurückzukehren. Precession bewirkt, dass die Sterne ihre Länge etwas jedes Jahr ändern, so dass das siderische Jahr ist länger als das tropische Jahr. Unter Beobachtung der Äquinoktien und Sonnenwenden stellte Hipparchus fest, dass die Länge des tropischen Jahres 36514-1300 Tage betrug oder 365.24667 Tage (Evans 1998, S. 209). Vergleichend mit der Länge des siderischen Jahres, berechnete er, dass die Rate der Präzession war nicht weniger als 1deg in einem Jahrhundert. Aus diesen Informationen kann man berechnen, daß sein Wert für das siderische Jahr 365141144 Tage beträgt (Toomer 1978, S. 218). Durch die Angabe eines Mindestsatzes hätte er eventuell Fehler in der Beobachtung erlaubt. Zur Annäherung an sein tropisches Jahr schuf Hipparchus seinen eigenen lunisolaren Kalender, indem er die von Ptolemäus im Almagest III.1 (Toomer 1984, S. 139) beschriebenen, von Meton und Callippus in On Intercalary Months and Days (jetzt verloren) modifizierte. Der babylonische Kalender benutzte einen Zyklus von 235 Mondmonaten in 19 Jahren seit 499 v. Chr. (Mit nur drei Ausnahmen vor 380 v. Chr.), Aber er benutzte keine festgelegte Anzahl von Tagen. Der Metonische Zyklus (432 v. Chr.) Verlieh diesen 19 Jahren 6,940 Tage, was ein durchschnittliches Jahr von 36514176 oder 365,26316 Tagen erzeugte. Der kallippische Zyklus (330 v. Chr.) Fiel eines Tages aus vier Metonischen Zyklen (76 Jahre) für ein durchschnittliches Jahr von 36514 oder 365,25 Tagen. Hipparchus sank ein weiterer Tag von vier Callipic-Zyklen (304 Jahre), die Schaffung der Hipparchic-Zyklus mit einem durchschnittlichen Jahr von 36514-1304 oder 365.24671 Tage, die in der Nähe seines tropischen Jahres von 36514-1300 oder 365.24667 Tage war. Die drei griechischen Zyklen wurden nie benutzt, um irgendeinen Zivilkalender zu regulieren - sie erscheinen nur im Almagest im astronomischen Kontext. Wir finden Hipparchus mathematische Unterschriften im Antikythera-Mechanismus, einem alten astronomischen Computer des 2. Jahrhunderts v. Chr. Der Mechanismus beruht auf einem Sonnenjahr, dem Metonischen Zyklus, der die Zeit, in der der Mond am selben Stern am Himmel erscheint, mit derselben Phase (Vollmond erscheint an der gleichen Position am Himmel etwa in 19 Jahren), der Callipic Zyklus (das sind vier Metonische Zyklen und genauer), der Saros-Zyklus und die Exeligmos-Zyklen (drei Saros-Zyklen für die genaue Eclipse-Vorhersage). Die Studie des Antikythera-Mechanismus beweist, dass die Alten sehr genaue Kalender verwendet haben, die auf allen Aspekten der Sonnen - und Mondbewegung am Himmel basieren. Tatsächlich stellt der Mondmechanismus, der Teil des Antikythera-Mechanismus ist, die Bewegung des Mondes und seiner Phase für eine gegebene Zeit unter Verwendung eines Zuges von vier Gängen mit einem Stift und einer Schlitzvorrichtung dar, die eine variable Mondgeschwindigkeit ergibt, die sehr nahe ist Das zweite Gesetz von Kepler, dh es berücksichtigt die schnelle Bewegung des Mondes bei Perigäum und langsamer Bewegung bei apoggee. Diese Entdeckung beweist, dass Hipparchus Mathematik weitaus fortgeschrittener war als Ptolemäus in seinen Büchern beschreibt, da es offensichtlich ist, dass er eine gute Annäherung an Keplers zweites Gesetz entwickelt hat. Mithraism war eine Geheimnisreligion oder - schule, die auf der Anbetung des Gottes Mithras basiert. Viele unterirdische Tempel wurden im römischen Reich von etwa dem 1. Jahrhundert v. Chr. Bis zum 5. Jahrhundert n. Chr. Gebaut. Das Verständnis des Mithraismus ist durch das nahezu völlige Fehlen schriftlicher Beschreibungen oder Schriftstellen erschwert worden. Die Lehren müssen aus der Ikonografie in der Mithraea rekonstruiert werden (ein Mithraeum war ein Höhlen - oder unterirdischer Treffpunkt, der oft Basreliefs von Mithras, den Tierkreis und die damit verbundenen Symbole enthielt ). Bis in die 1970er Jahre folgten die meisten Gelehrten nach Franz Cumont, um Mithras mit dem persischen Gott Mithra zu identifizieren. Die Cumonts-These wurde 1971 erneut untersucht, und Mithras gilt heute als eine synkretistische Gottheit, die nur wenig von der persischen Religion beeinflusst wird. Der Mithraismus wird als ausgeprägte astrologische Elemente anerkannt, aber die Details werden diskutiert. Ein Gelehrter des Mithraismus, David Ulansey, hat Mithras (Mithras Sol Invictus - die unbesiegbare Sonne) als zweite Sonne oder Stern interpretiert, die für die Präzession verantwortlich ist. Er schlägt vor, dass der Kult von der Hipparchus-Entdeckung der Präzession inspiriert worden sein könnte. Ein Teil seiner Analyse basiert auf der Tauroktonie, einem Bild von Mithras, das einen Stier opferte, der in den meisten der Tempel gefunden wurde. Laut Ulansey ist die Tauroktonie eine Sternkarte. Mithras ist eine zweite Sonne oder hyperkosmische Sonne und die Konstellation Perseus, und der Stier ist Taurus, eine Sternbild des Tierkreises. In einer früheren astrologischen Zeit hatte die Frühlingsnachtgleiche stattgefunden, als die Sonne im Stier war. Die Tauroktonie, durch diese Argumentation, gedenkt Mithras-Perseus Ende des Zeitalters des Stiers (etwa 2000 v. Chr. Auf der Vernal Equinox oder etwa 11.500 v. Chr. Auf der Grundlage der Herbst-Tagundnachtgleiche). Die Ikonographie enthält auch zwei Fackellagerjungen (Cautes und Cautopates) auf jeder Seite des Tierkreises. Ulansey und Walter Cruttenden in seinem Buch "Lost Star of Myth and Time", interpretieren diese als Mittel des Wachstums und des Verfalls oder der Aufklärung und Dunkelheit, die ursprünglichen Elemente der kosmischen Progression. Somit wird angenommen, dass der Mithraismus etwas mit den sich ändernden Zeitaltern innerhalb des Präzessionszyklus oder des Großen Jahres zu tun hat (Platonischer Ausdruck für eine vollständige Präzession des Äquinoktiums). Umwandlung der Pole Sterne Präzession der Erde Achse um den Norden ekliptischen Pol Precession der Erde Achse um den Süden ekliptischen Pol Eine Folge der Präzession ist ein wechselnder Stern Stern. Gegenwärtig ist Polaris sehr gut geeignet, um die Position des nördlichen Himmelsstabes zu markieren, da er etwa einen halben Grad davon entfernt ist und ein moderat heller Stern ist (optische Größe ist 2,1 (variabel)). Auf der anderen Seite ist Thuban im Sternbild Draco, der 3000 v. Chr. Der Polarstern war, bei 3,67 (ein Fünftel so hell wie Polaris) viel weniger auffällig, heute ist er im lichtverschmutzten städtischen Himmel nur noch unsichtbar. Die brillante Vega in der Konstellation Lyra wird oft als der beste Northstar angepriesen, als sie diese Rolle um 12000 v. Chr. Erfüllte und dies wieder um das Jahr 14000 tut. In Wirklichkeit kommt sie niemals näher als 5 an die Pole. Wenn Polaris der Nordstern um 27800 n. Chr. Sein wird, wird er aufgrund seiner richtigen Bewegung weiter weg von der Stange sein, als er jetzt ist, während er 23600 v. Chr. Näher an der Stange herankam. Um in diesem Augenblick den südlichen Himmelsstab am Himmel zu finden, ist man weniger glücklich, da dieser Bereich ein besonders langweiliger Teil des Himmels ist und der nominale Südpolstern Sigma Octantis ist, der bei 5,5 kaum sichtbar ist Richtig dunklen Himmel. Doch das wird sich im 80. bis 90. Jahrhundert ändern, wenn der Südhimmelsstock durch das Falsche Kreuz geht. Man sieht auch, dass der Südpol, der für die letzten 2000 Jahre von dem Südkreuz schön angedeutet wurde, sich auf diese Konstellation zubewegt. Folglich ist es jetzt nicht mehr aus subtropischen nördlichen Breiten zu sehen, wie es in der Zeit der alten Griechen war. Die in vielen astronomischen Büchern gefundenen Bilder sind nur erste Approximationen, da sie die variable Geschwindigkeit der Präzession, die variable Schräge der Ekliptik, die planetarische Präzession (die nicht den ekliptischen Pol im Mittelpunkt bildet, nicht berücksichtigen), nicht berücksichtigen Ein Kreis ungefähr 6 weg von ihm) und die korrekten Bewegungen der Sterne. Polar Shift und Equinoxes Shift Precessional Bewegung als von außerhalb der Himmelskugel gesehen. Die Rotationsachse der Erde beschreibt über einen Zeitraum von etwa 25800 Jahren einen kleinen Kreis (blau) zwischen den Sternen, der um den ekliptischen Nordpol (blau E) und mit einem Winkelradius von etwa 23,4: der Winkel, der als die Schiefstellung der Ekliptik. Die orange Achse war die Erde-Drehachse vor 5000 Jahren, als sie auf den Stern Thuban zeigte. Die gelbe Achse, die auf Polaris zeigt, ist jetzt die Situation. Beachten Sie, dass, wenn die himmlische Sphäre von außen gesehen wird Konstellationen erscheinen in Spiegelbild. Beachten Sie auch, dass die tägliche Rotation der Erde um ihre Achse entgegengesetzt zur Präzessionsrotation ist. Wenn die Polarachse von einer Richtung zur anderen vorangeht, bewegt sich die Äquatorialebene der Erde (angezeigt durch das kreisförmige Gitter um den Äquator) und den zugehörigen Himmelsäquator. Wo der Himmelsäquator die Ekliptik schneidet (rote Linie), gibt es die Äquinoktien. Wie aus der Zeichnung zu ersehen, die orange Raster, vor 5000 Jahren ein Schnittpunkt von Äquator und Ekliptik, war die Frühlingsäquinoktikum nahe dem Stern Aldebaran von Taurus. Inzwischen (das gelbe Gitter) hat es sich (roter Pfeil) zu irgendwo in der Konstellation der Fische verschoben. Beachten Sie, dass es sich hierbei um eine astronomische Beschreibung der Präzessionsbewegung handelt und dass die Vernal-Äquinoktisposition in einer gegebenen Konstellation nicht die astrologische Bedeutung eines gleichnamigen Zeitalters impliziert, da sie (im Alter und in der Konstellation) nur eine exakte Ausrichtung im ersten Punkt haben Von Widder, dh einmal in jeder ca. 25800 (großes siderisches Jahr). Gleiches Bild wie oben, aber jetzt von (nahe) Erdperspektive Für den Nicht-Astronomen mag es nicht direkt klar sein, was die Verschiebung der Äquinoktien mit der Präzession der Rotationsachse der Erde zu tun hat. Die Figuren versuchen das zu erklären. The rotation axis of the Earth describes over a period of 25700 years a small circle (blue) among the stars, centred around the ecliptic northpole (blue E) and with an angular radius of about 23.4: the angle known as the obliquity of the ecliptic. The orange axis was the Earths rotation axis 5000 years ago when it pointed to the star Thuban. The yellow axis, pointing to Polaris is the situation now. Note that when the celestial sphere is seen from outside (as in the first drawing, an impossibilty of course) constellations appear in mirror image. Also note that the daily rotation of the Earth around its axis is opposite to the precessional rotation. Of course when the polar axis precesses from one direction to another, then the equatorial plane of the Earth (indicated with the circular grid around the equator) and the associated celestial equator will move too. Where the celestial equator intersects the ecliptic (red line) there are the equinoxes. As seen from the drawing, the orange grid, 5000 years ago one intersection of equator and ecliptic, the vernal equinox was close to the star Aldebaran of Taurus. By now (the yellow grid) it has shifted (red arrow) to somewhere in the constellation of Pisces. This is why the equinoctial shift is a consequence of the precession of the rotation axis of the Earth and the other way around. The second drawing shows the perspective from a near Earth position as seen through a very wide angle lens (from which the apparent distortion). Explanation The precession as a consequence of the torque exerted on Earth by differential gravitation. The precession of the equinoxes is caused by the differential gravitation forces of Sun and Moon on Earth. In popular science books one often finds this explained with the analogy of the precession of a spinning top. Indeed it is the same physical effect, however, some crucial details differ. In a spinning top it is gravity which causes the top to wobble which in its turn causes precession. The applied force is thus in the first instance parallel to the rotation axis. But for the Earth the applied forces of the Sun and Moon are in the first instance perpendicular to it. So how then can they cause it The answer is that the forces do not work on the rotation axis. Instead they work on the equatorial bulge due to its own rotation, the Earth is not a perfect sphere but an oblate spheroid, the equatorial diameter about 43 km larger than the polar. If the Earth were a perfect sphere, there would be no precession. The figure explains how this works. The Earth is given as a perfect sphere (so that all gravitational forces working on it can be taken equal as one force working on its center), and the bulge is approximated to be a torus of mass (blue) around its equator. Green arrows indicate the gravitational forces from the Sun on some extreme points. These forces are not parallel as they all point towards the centre of the Sun. Therefore the forces working on the northernmost and southernmost parts of the equatorial bulge have a component perpendicular on the ecliptical plane and directed towards it. We find them (small cyan arrows) when the average gravitation force on the centre of the Earth is substracted (because this force will be used as the centripetal force for the Earth in its orbit around the Sun). In all cases in addition to these tangential components there will be also radial components, but they are not shown as they do not contribute to the precession (they contribute to the tides). It is now clear how these tangential forces create a torque (orange), and this torque added to the rotation (magenta) shifts the rotation axis slightly to a new position (yellow). Repeat this again and again, and one sees how the axis precesses along the white circle, which is centred around the ecliptic pole. It is important to note that the torque is always in the same direction, perpendicular onto the direction in which the rotation axis is tilted away from the ecliptic pole, so that it does not change the axial tilt itself. It is also important to note that the torque is everywhere the same, whatever position of the Earth is in its orbit around the Sun. The precession is thus always steadily progressing and does not change with the seasons. Although the above explanation involved the Sun, the same story holds true for any object moving around the Earth along (or close to) the ecliptic, i. e. the Moon. The combined action of the Sun and the Moon is called the lunisolar precession. In addition to the steady progressive motion (resulting in a full circle in 25700 years) the Sun and Moon also cause small periodic variations, due to their changing positions. These oscillations, in both precessional speed and axial tilt are known as the nutation. The most important term has a period of 18.6 years and an amplitude of less than 20 arcseconds. In addition to lunisolar precession, the actions of the other planets of the solar system cause the whole ecliptic to slowly rotate around an axis which has an ecliptic longitude of about 174 measured on the instantaneous ecliptic. This planetary precession shift is only 0.47 arcseconds per year (more than a hundred times smaller than lunisolar precession), and takes place along the instantaneous equator. The sum of the two precessions is known as the general precession. Effects of Axial Precession on the Seasons This figure illustrates the effects of axial precession on the seasons, relative to perihelion and aphelion. The precession of the equinoxes can cause periodic climate change (see Milankovitch cycles ), because the hemisphere that experiences summer at perihelion and winter at aphelion (as the southern hemisphere does presently) is in principle prone to more severe seasons than the opposite hemisphere. Hipparchus estimated Earths precession around 130 BC, adding his own observations to those of Babylonian and Chaldean astronomers in the preceding centuries. In particular they measured the distance of the stars like Spica to the Moon and Sun at the time of lunar eclipses, and because he could compute the distance of the Moon and Sun from the equinox at these moments, he noticed that Spica and other stars appeared to have moved over the centuries. Precession causes the cycle of seasons (tropical year) to be about 20.4 minutes less than the period for the earth to return to the same position with respect to the stars as one year previously (sidereal year ). This results in a slow change (one day per 71 calendar years) in the position of the sun with respect to the stars at an equinox. It is significant for calendars and their leap year rules. How Intelligent Are Cats Copyright 2004-2014, Sarah Hartwell Cat owners often claim that cats are too intelligent to do the sort of tricks that dogs do willingly. Others believe cats are unintelligent because its harder to train them to do tricks. In this article (on 2 pages) I aim to explain some of these differences and explore feline intelligence and the limitations on feline intelligence. This also means looking at how cats see the world and at some aspects of natural cat behaviour. Unfortunately for cats, they are often non-consenting participants in surgically intrusive experiments to assess learning and intelligence. Humans seem to feel it necessary to assess the intelligence of animals as a way of reinforcing our own sense of superiority and the cat has been a favourite subject for studying learning and brain function for over a century. Many tests insert electrodes into cats brains either to monitor brain activity or stimulate certain behaviour others involve deliberately injuring the brain to see whether learning capacity or intelligence is affected. Most such test subjects are killed and their brains further dissected to look for evidence of brain changes resulting from learning. I personally consider these experiments cruel and gratuitous (their medical benefit to humans is too often dubious) and though some such experiments are referenced here, Messybeast does not support this form of experimentation. In recent years there has been an increase in tests in a more natural home-type environment rather than an artificial laboratory environment. While lab conditions are more easily manipulated, they do not bring out the best in test subjects and give misleading results. Better tests also take into account an animals innate behaviours and instincts, things which have previously counted against cats in classical laboratory tests. This article also considers some of the anecdotal evidence for intelligence reported by owners, but frequently dismissed by laboratory researchers. Since cats operate in the natural world, it makes sense to observe them in their own environment and not just in highly controlled, artificial laboratory environments. The Truth About Cats and Dogs Dogs have been trained to guardprotect, herd, hunt, searchrescue, assist (e. g. guide dogs for the blind) and perform circus tricks, obedience or agility classes. To many, this is a clear sign of their intelligence and the superiority of the canine intellect over feline intelligence. Cats have been trained to perform tricks as seen on films or TV advertisements, but do not have the same repertoire as dogs. This leads to the obvious conclusions that cats are neither intelligent enough nor co-operative enough to be trained. For example, in experiments where cats and dogs were expected to navigate mazes, most cats performed badly. Dogs soon learned to navigate the maze and reach the reward. Cats sat down and washed. They investigated blind alleys. They did not complete the maze in the allocated time and were therefore judged as failing the test or lackadaisical. Eager-to-please dogs learned that they got a reward for learning the. Cats are not motivated in this way. Being opportunists, investigating every blind alley made sense to the cat - after all, who knows where prey might be hiding in the real world Sitting down and washing is a displacement activity when a cat is uncertain. Most of the canine activities cited earlier rely upon manipulating canine social instincts. Dogs live, hunt and play in hierarchical social packs headed by an alpha male and alpha female. They frequently co-operate in raisingguarding the alpha pairs young and co-operate to hunt large prey. Juveniles beg submissively for food from adults. They are eager to pleaseappease pack-mates in order to remain part of their pack and they demonstrate submissiveness to higher ranking animals. Domestic dogs view humans as dominant pack members so they are eager to please us. In addition, dogs have been selectively bred over hundreds of years to enhance some traits and reduce or eliminate others. Cats, meanwhile, have a different social structure. Where food is plentiful they are largely solitary although females, usually related ones, may form social groups. Males tend to roam in search of females rather than remain as part of a group. Where food sources are localised (e. g. a rubbish dump) they form colonies but the social structure is more akin to that of lions - groups of females who may co-operatively raise young. Unlike lions, cats do not generally hunt prey larger than themselves and rarely hunt in pairs or groups. Cats are, therefore, independent rather than truly social and have little or no need to co-operate with other cats. Feline co-operation with humans is limited unless it serves the individual cats interests to perform a task. Whereas dogs have been bred for utility, cats have been bred solely for appearance. Dogs are largely motivated by the pack-living instinct i. e. they will perform purely for praise and acceptance dished out by the dominant pack member (i. e. the owner or trainer). They will also perform because, in the wild, they risk being driven out of a pack or being demoted to pariah position. Cats are not motivated by social status factors. To train a cat you must find out what motivates it. Usually this means food, or at least conditioning it that there is the promise of food at the end of the session. Even then, cats are not motivated by food in the same way as dogs - if achieving the food reward is too much hard work, cats frequently cut their losses and go in search of easier prey. In the wild, it makes no sense for a solo hunter to expend more energy on finding or killing prey than it gets from eating that prey. While dogs will track and pursue prey over long distances and wear down their quarry, cats hunt by waiting in ambush and pursuing prey for short distances only. Starving a cat does not make it easier to train either, cats are better than dogs at ignoring hunger pangs. For young cats, although food is a powerful reward, activities such as manipulation of simple objects such as a ball or scrunched up paper, or the chance to explore an unfamiliar space can be adequate rewards in some tasks. There will always be some cats who not only learn easily, but appear to relish learning, though these are the exception rather than the rule. Because we judge intelligence by comparing other creatures to ourselves, many popular accounts of cat behaviour describe learning as though cats are mentally defective humans rather than highly specialised carnivores. For example, in 1915 L T Hobhouse (Professor of Sociology at the University of London) wrote: I once had a cat which learned to knock at the door by lifting the mat outside and letting it fall. The common account of this proceeding would be that the cat did it in order to get in. It assumes the cats action to be determined by its end. Is the common account wrong Let us test it by trying explanations found on the more primitive operations of experience. First, then, can we explain the cats action by the association of ideas The obvious difficulty here is to find the idea or perception which sets the process going. The sight of a door or a mat was not, so far as I am aware, associated in the cats experience with the action which it performed until it had performed it. If there were association, it must be said to work retrogressively. The cat associates the idea of getting in with that of someone coming to the door, and this again with the making of a sound to attract attention, and so forth. Such a series of associations so well adjusted means in reality a set of related elements grasped by the animal and used to determine its action. Ideas of persons, opening doors, attracting attention and so forth, would have no effect unless attached to the existing circumstances. If the cat has such abstract ideas at all, she must have something more - namely, the power of applying them to present perception. The ideas of calling attention and dropping the mat must somehow be brought together. Further, if the process is one of association, it is a strange coincidence that the right associates are chosen. If the cat began on a string of associations starting from the people in the room, she might as easily go on to dwell on the pleasures of getting in, of how she would coax a morsel of fish from one or a saucerful of cream from another, and to spend her time in idle reverie. But she avoids these associations, and selects those suited to her purpose. In short, we find signs on the one hand of the application of ideas, on the other of selection. Both of these features indicate a higher stage than that of sheer association. Hobhouse interpreted his cats behaviour as having purposeful elements though he offers an alternative behaviourist explanation: an association between the motivation and pleasure of getting through the door, and the action of lifting and dropping the mat. Early Stimulus-Response Theories Early psychologists believed all behaviour resulted from stimulus-response associations. Their theories had no room for thinking, consciousness, instinct, innate behaviours or a predisposition to certain behaviours. At its simplest level, learning involves linking together (associating) previously unrelated stimuli, or actions and the consequences of those actions. Many invertebrate animals are capable of forming such associations. Early researchers had discovered hard-wired behaviours, but extrapolated that all behaviours were simple stimulus-response reflexes. In 1966, Fernand Mery wrote: American neurophysiologists at Yale University are achieving success in a different field. Dr Joseacute Delgado installed a complete series of electrodes in the brain of a cat. The operation took place under complete anaesthesia, and when the cat woke up, he knew nothing about what had happened. Experiments did not begin until everything had healed perfectly. It is impossible not to feel for this laboratory cat, but those who were present and took part in the experiment confirm that he made no attempt to escape. He even seemed to appreciate the situation, as if appreciating the interest that was being taken in him. Not knowing anything about the surgical operation to which he had been submitted, he behaved as if he were obeying a simple friendly drill: he became a robot. Around his neck, one might distinguish a small collar on to which is fixed a receiving set with tiny transmitters, to which are attached neat silver wires, each of which corresponds to a cerebral localisation and disappears into his fur. By this means, whether in the same room or hundreds of miles away, and by a radio-transmitted command, the cat can experience the need to drink (and he has water and milk placed at his disposal), to eat (he can choose whatever he wants), to itch (and can scratch himself as much as he wants). It is even possible, by stimulating such and such a part of the frontal lobes, to provoke in him an overwhelming affection or an aggressive antipathy and, in the very next moment, to reduce these states. The importance of this experiment is not that one can oblige the cat to perform such and such a movement, but one can simply, by passing an electric current, waken in him the desire to act in a determined direction. At present such experiments towards a better knowledge of feline psychology are not being regularly followed up though they have been renewed with monkeys and, for some time now, with humans. These same minute electrodes are planted in specifically chosen points which relate to the psychic disorders presented by the subjects. In this way it is possible to make tests whose results are extremely illuminating for psychiatrists. These results are at present being published by the New York Academy of Science. It goes without saying that they may provide us with some frightening perspectives on the human mind. In the past, psychologists believed all learning to be simple association. The stimulus-response reflex-action theory was also considered true for humans. It is now thought that many mammals are capable of more complex mental processes. Most higher animals have some sort of mental representation of their world, and how the world works, which they consult whenever they have to make a decision. It may never be possible to truly understand how a cat perceives and understands the world. Virtual reality can give us an idea of what the world looks and sounds like to a cat by adjusting the signals which reach our eyes and ears and by filming from cats-eye level, but however much scientists poke electrodes into the brains of unfortunate felines, they cannot truly get inside their minds. To investigate feline intelligence and learning abilities, we must devise better suited, and more humane, tests. To do that, we must understand how cats have evolved to suit their environment and lifestyle, things that which predispose them to behave in certain ways. One of the simplest forms of learning is Pavlovian conditioning (Pavlovian Learning). This involves associating a stimulus with an event. One stimulus, called the Unconditioned Stimulus, is normally linked to a particular motivational state and results in an innate reaction called the Unconditioned Response. For example, if the Unconditioned Stimulus is the smell of food and the motivational state is hunger, then the UCR is drooling If a Conditioned Stimulus such as a buzzer, occurs just before, or at the same time as, the Unconditioned Stimulus then it results in the Unconditioned Response even on its own. The Unconditioned Response becomes a Conditioned Response and the conditioned subjects drool at the sound of the buzzer. In a cats natural environment, an Unconditioned Stimulus might be the pain inflicted by an aggressive tom cat. The Unconditioned Response will probably be flight to avoid a repetition of the pain. In the future, the mere sight of the aggressor (now a Conditioned Stimulus) might result in flight i. e. a Conditioned Response because the cat is motivated to avoid pain. If the Conditioned Stimulus (the aggressive tom cat) is in the distance the cat is motivated to avoid detection and the Conditioned Response is to freeze instead of flee. Pavlovian conditioning forms a link between the original stimulus and the conditioned stimulus, but the actual response depends on the cats motivational state. Conditioned learning is complicated by an animals innate behaviours. Cats ears are designed to home in on noises like small rustling prey in long grass. In an experiment, arrival of food was signalled by 10 seconds of a clicking sound from a loudspeaker 2 metres away from the food dispenser. The cats ran towards the sound, searched around the loudspeaker or even attacked it. Some ignored the actual food and concentrated their attentions on the loudspeaker. It took hundreds of trials to condition the cats to go to the food dispenser when they heard the clicks. In the same experiment, rats did not investigate the loudspeaker, but quickly associated the sound with the arrival of food. This was not because the cats were stupid. To cats, sound indicates the apparent location of prey and they reacted according to their instincts. Highly adapted predators expect to find the prey noises and the prey itself (the food) at the same location. Cats quickly learn when a Conditioned Stimulus is unreliable and they can un-learn an unreliable Conditioned Response, ignoring bells, buzzers, clicks or whatever as irrelevant. Humans are biased in assessing the intelligence of other species, judging them according to their similarity to ourselves. Animals having good eyesight and dextrous hands are consistently rated as more intelligent than animals lacking those features. We are biased towards animals that see, react to and manipulate things in a similar way to ourselves. Animals that learn to do things useful to humans are also rated as more intelligent than less co-operative creatures. This is a shortfall in human worldview, not in animal intelligence. Animals that rely largely on instinct or highly context-specific learning (i. e. only learns things related to the environment it evolved to live in) can only readapt at a pace determined by evolutionary mechanisms. Those with more extensive learning abilities can alter their behaviour patterns rapidly. Cats also have ecologically surplus ability i. e. the capacity to solve problems outside of its specific adaptations to its environmental niche. Ecologically surplus abilities allow animals to cope with rapid or unexpected change in the environment, but are hard to measure. The cats ecologically surplus abilities are demonstrated by its ability to move from pampered pet to feral feline and back again, within a very few generations, or even within the lifetime of a single cat. Humans often define intelligence as IQ. This is misleading because there are different scoring systems for IQ and it is possible to learn how to perform well at IQ tests. There are also intelligent people who dont perform well at IQ tests because the tests are biased to certain types of intelligence (e. g. logical reasoning) and are culturally skewed. Other tests include the ability to learn and remember. Is the ability to learn by rote a sign of intelligence If so, any avian mimic is intelligent. Intelligence comprises many things - the ability to understand and utilise ones environment the ability learn and remember facts (store knowledge) the ability to link facts the ability to apply knowledge and to adapt it to new situations the ability to override or adapt an instinctive response. A cat or dog does not need to learn nuclear physics or understand Shakespeare in order to survive. Animal intelligence is linked to the animals natural environment and its survival needs. To measure its intelligence we must adapt our perception of intelligence to its world-view and formulate tests appropriately. If the test relies on learning, we must find out what motivates a dog or a cat to learn or to perform Different animals ecology means different motivating factors We need tests which apply to the animals physical and behavioural traits and constraints, not to our own constraints. We also need some way to compare their very different behaviours. Different animals have different innate behaviours. For example, an untrained cat and an untrained Border Collie dog are both presented with a group of ducklings. The dog herds the ducklings and protects them. The cat stalks the ducklings and eats one or more of them. Is the cat unintelligent because it doesnt herd the ducklings Is the dog unintelligent because it fails to identify those ducklings as prey and it doesnt take advantage of a meal opportunity Neither creature is more or less intelligent than the other if judged by this test. Both performed according to their instinct. The dog came from a breed with a strong herding instinct enhance by human selection over generations it does what comes naturally to Border Collies. The cat does what comes naturally to cats and identifies an easy meal, but fails the herding test. The test is either poorly chosen or is biased towards herding dogs the results are open to interpretation and the conclusions are worthless. Such tests are sometimes used by researchers with hidden agendas i. e. those who simply need statistics to prove a pet theory or a foregone conclusion. Finally, humans are very protective of intelligence. Indications of intelligence in other animals are often termed cunning or are written off as instinct. As a race, we do not like to admit that intelligence is not exclusively a human trait. Much the same has been true in human history where white Europeans regarded non-white humans (so-called lesser races) as cunning and able to be trained, but not intelligent. Humans, as well as cats, have a degree of hard-wired behaviours. These hard-wired behaviours allow us to do routine tasks on autopilot and free up more of the brain for solving other challenges. Horses for Courses - and Tests for Species An animals ability to master an experimental task often has less to do with intelligence than with constraints imposed by physical traits and behavioural predispositions. Species differ in how they see or hear the visual or auditory cues they are being taught to respond to, just as a human cant learn to respond to an ultrasonic or ultraviolet cue as these fall outside of our hearing and visual ranges. Animals differ in the type of rewards they are willing to work for. They differ in the things they are wary of, or even frightened of, and which will interfere with learning or will entirely undermine an experiment e. g. a cat will not learn to pick a certain plastic shape if the plastic has an offensive odour. Animals are also predisposed (prepared) to learn certain types of associations, and are predisposed not to learn others (contra-prepared). It is a matter of how their brain-wiring has evolved, predisposing them to interact with their environment in certain ways. If a test or the type of reward doesnt somehow fit into what a cat is predisposed to doing (e. g. manipulating an existing behavioural trait), then the cat wont do it When trying to measure the relative intelligence of different species (a behaviour that obsesses the human species), some animals do poorly at learning certain things, but if the experiment is redesigned to better suit a species behavioural or perceptual traits, and it takes into account what the species is predisposed to doingnot doing, the same animals do much better. Despite being favourite research subjects for over a century, cats are particularly challenging subjects for intelligence testing. It is hard to get them to show how they learn or what they know, especially in a laboratory setting. While social animals like dogs and horses respond to social rewards and to punishment, these are almost meaningless to cats. Although cats may enjoy being petted, it doesnt have the significance of acceptance by a superior in the same way it does for dogs. They are indifferent to the concept of petting as a reward and withholding petting as a punishment in fact ignoring a cat can be counter-productive as this is a sign of courtesy in feline terms Punishing a social animal (by ignoring it, speaking harshly or by physical punishment) equates to social disapproval or exclusion from the social group. Whiles this works for dogs, cats are either non-social or have a loose social structure and respond to the same punishment with the fight or flight reaction. Having evolved to be self-sufficient, they lack the urge to appease social superiors or gain acceptance into a pack or herd - they are more likely to go away for a few hours and wait for the human participant to calm down. Dogs, rats and other research subjects will learn specific, focussed tasks to gain a food reward. Cats are self-sufficient, solitary, opportunist hunters and have evolved to cope with periods of hunger because only around one in three hunts result in a meal. In experiments where cats which had not been fed for a whole day were tested for their ability to locate an object hidden behind a screen, the researchers noted that the cats searches were slow or lackadaisical even though the rewards for finding the object were the cats favourite food treats. In the wild, cats are opportunists and investigate their territory for places likely to conceal prey so the lackadaisical test subjects were less motivated by the food treat than by checking all potential prey hiding-holes. It is obvious to pet owners, and to naturalists observing feral cats, that cats are innately curious and they can and do learn. In the home or natural wild environment, cats adapt their behaviour and strategies according to circumstances. There are cats that play fetch, open door handles or break into packages every bit as fiendish as laboratory puzzle-boxes. Well-designed experiments that take into account the cats physical abilitieslimitations and innate feline behavioural traits show cats to be inquisitive, intelligent and able to learn. Reflex action and conditioned learning are good for some behaviours, but a different type of learning is needed for more flexible behaviour, one which enables the cat to predict the consequences of its own actions, and modify its actions based on past successes and failures. It is a survival requirement that animals learn that some foods are toxic or taste bad after only one mistake and will then avoid that food. This is known as Instrumental Learning or trial-and-error. In Thorndikes puzzle-boxes, cats first clawed and scratched indiscriminately at the sides of the cage, until accidentally discovering the lever, string etc that let them out. Their later attempts were less random. Some puzzle-boxes were quite complex. One latch required a simultaneous lift and push, and in other cages two or even three latches had to be opened in the correct sequence. Not all cats mastered these, but some did. The skills were gained gradually and Thorndike concluded The gradual slope of the time-curve, then, shows the absence of reasoning. They represent the wearing smooth of a path in the brain, not the decisions of a rational consciousness. This is a generalisation as some cats improved abruptly and made no further mistakes even if months elapsed between tests. We describe the abrupt improvement as the penny has dropped or something has clicked. One of my cats, Affy, was almost impossible to litter train despite 18 months of effort. One day she watched another cat using a litter tray and the penny dropped from then on she used the litter tray (she had also learned through observation, something Ill look at later in this article). In early classical psychological experiments, cats readily learned to escape from puzzle boxes by manipulating strings or levers in certain sequences. Having learned one puzzle box, they quickly mastered others as any owner of a feline escape artist will confirm. Though they learned to manipulate levers and strings, they could never learn the secret of getting out of the box when the experimenter opened the door to the box only when the cat scratched or licked himself. If a cat accidentally dislodged the latch with its tail, it did not learn anything about where the latch was or how it opened. Associating an instinctive manipulative action like pawing an object with some external real-world consequence is a natural action that the cats brain is predisposed to learn its natural (which is why so many cats learn to scoop food from a can using their paw like the ArthursKattomeat cat). Associating an instinctive grooming action like licking or scratching with some external real-world consequence is highly unnatural and cats cannot learn it. In the wild, the skills most useful for survival are acquired most easily. It is easier to train a cat to obtain a food reward by using a normal part of its behavioural repertoire, such as hooking back a bolt with its paw (the same movement is used to dislodge prey that takes refuge in a crevice), than by an arbitrary but straightforward action, such as pushing an identical bolt inwards. Cats instinctively know to hook things out, not to push things further in However, cats sometimes look for other solutions: In an experiment carried out by Professor Julius Masserman in America, two cats apparently out-thought the humans. They deliberately jammed the mechanism they were meant to operate each time they wanted food. The cats found that by wedging an electric lever into a corner of their cage, the feeder functioned continuously, dispensing food with no further effort on the part of the cats. Whether the cats discovered this by accident and repeated it, wasnt clear in the 1950s report I had. If it is possible to train a cat to operate a lever, it is certainly possible for a cat to learn how to disable the lever. Another example of associating a manipulative action with a real-world consequence is when your cat scratches politely at a door (or window) to attract your attention so that you open the door for it to go in or out. Having learnt the you will open the door for it on at least some of the occasions, it is much harder for the cat to unlearn the lesson. If you ignore it, it will go away and then try again later, so to train it not to expect the door to open, you have to ignore it consistently. One of my cats, Squeak, learnt that pulling a certain branch and releasing it so it hit the door with a loud thump was even more effective at getting the door opened. Of course, Squeak could not know that my real reason for letting her in was to keep the glass panel intact Many cats also learn that humans communicate through vocalisation and they modify their natural manipulative action (pawing or clawing) and mew at the door or cupboard instead. In essence they are associating 2 lessons (manipulative action vocal communication) and modifying their own behaviour to get the desired response from their human. Not just a sign of intelligence, but a case of who is training whom Now back to the puzzle boxes. To your cat, a cat carrier is a puzzle box. Cats learn which side has the opening and often learn to associate the strap-and-buckle fastening with an exit and butt, paw or bite at the door andor the fastener. If they loosen it enough to escape, the lesson is quickly learnt, often repeated and quickly applied to other cat carriers - having learnt there is a closure mechanism, the cat learns to look for closure mechanisms on any other carrier you put it in. Some owners claim their cats have learned to pee in the corner of a cardboard pet carrier and escape through the resulting papier macheacute - what started as a nervous accident can quickly become a learned behaviour The problem is, the cat is probably not peeing in order to open the carrier, it is peeing because it is frightened by the carrier (having learned to associate the carrier with the unwelcome ministrations of the vet) and its escape from soggy cardboard is an accidental consequence. The same nervous cats still pee in plastic carriers even after consistently failing to escape from the carrier. Like licking, peeing is an instinctive behaviour and it is unnatural to associate it with an external real-world consequence. Such intelligence can also be their undoing. Some cats, such as my own Scrapper (one of felinitys brighter sparks), never grasp that cat flaps can be pushed open in both directions having learnt to push from one side to get out, they awkwardly pull the flap open on the other side when coming in. Cats are also motivated to get into certain types of puzzle box. A food cupboard, a carton or a fridge door is also a puzzle box and the cat soon learns which edge of the door to pull at in order to open it. One enterprising Siamese cat learned to bite a hole in a milk carton, as far down the carton as possible, to get the maximum amount of milk out of it Cats view their owners as equals and when a cat tries to please you it does so on its terms, not yours. Cats are also adept at manipulating their owners those whose cats enjoy playing fetching games might reflect on who taught whom the game. In all likelihood, the cat initiated the retrieving game and trained the owner to throw the object. One of my first cats, Scrapper, regularly retrieved his favourite wand-type toy from a bookshelf and brought it to me - but only when Scrapper wanted a game. The following series of photos are from psychological testing of cats at brooklynCollege in the early 1940s. The show cats learning to open the puzzle box to get a food reward. In one experiment, 2 cats co-opearted to haul the food towards them. In another, the cats competed to get to the food before the other. And finally, a kitten learns to navigate a maze. How Cats See the World How intelligence is expressed is largely determined by how the sense organs and motor abilities (e. g. whether it can manipulate objects) operate. Evolution is economical and an animals brain is wired up according to what sensory inputs it can receive and what its limbs are capable of doing. An animals brain is wired up according to what is important for its survival. If it relies on vision for hunting, the brain areas related to receiving and processing visual stimuli will be well developed. If it relies on smell, the region for processing smell will be well developed. An important sense gets more brain-space at the expense of a less important one. The neocortex region (grey matter) of the brain plays a crucial part in learning and is highly specialised according to species. In diurnal humans it contains a large visual area and a large area for fine motor control of our hands. We excel at intelligence tests that require visual abilities and fine manipulation of objects. Cats are crepuscular (active at duskdawn) and rely particularly on their hearing, hence a large region of neocortex is devoted to processing sounds. This is enhanced by their highly mobile ears. The importance of hearing is evident in blind cats, many of which can catch prey or chase toys, relying entirely on sound. Most humans have excellent colour vision, about 120 o of stereoscopic vision (giving good depth perception), relatively good hearing in a limited frequency range (but not mobile ears) and a comparatively poor sense of smell. We find it hard to imagine how other animals with differently tuned senses perceive the world and intelligence tests were geared towards creatures with human-like sensory abilities. Cats perceive the world quite differently. Like humans, they have forward facing eyes and stereoscopic vision and can judge size, distance and depth essential for stalking and pouncing on prey. Cats have about 90 o to 130 o of stereoscopic vision, depending on breed-specific traits such as face shape. Otherwise, they view the world quite differently. Intrusive studies measuring electrical nerve impulses in cats brains show their colour perception is very different. Animals with poor colour vision, do poorly at learning tests which require them to distinguish between different coloured objects. In brief, the human retina (back of the eye) has three types of cone cell (colour receptors) sensitive to red, green and blue. Nerve cells pick up the relative amounts of red, green and blue and our brain translates this into the various colours of the spectrum. We can distinguish around 100 distinct hues. The other type of cell in the retina are rods these are sensitive to light and dark. Because we evolved for daytime living, we have relatively few rods and hence have poor vision in dim light. Cats have cones sensitive to green and blue, but few, if any, cones for red. To a cat, red, orange, yellow and green are seen as one colour. Blue and violet are seen as another colour. Other hues are variations on these two colours (much as monochrome photos are different shades of grey). They can tell that a red object is not black, grey or white, but cannot distinguish it from a green object. Cats are more active in dim light where colour vision is less important than good night vision, so much more of the retina is given over to rod cells. They have enough colour vision to help them spot camouflaged predators, but most owners will have noticed how cats often miss toys (or prey) until the object moves. This is because rods are also very good when it comes to detecting movement (the pattern of light and shade changes when something moves). Cats have other adaptations for dim light. Behind the retina is a reflective layer called the tapetum lucidum. This bounces light back through the retinal cells, amplifying available light (like night-sight binoculars). This is what makes cats eyes glow yellow-green in car headlights or flashlit photos. Cats have different visual acuity (sharpness) to humans. Acuity is linked to the size and structure of the eye. High visual acuity give a sharper image while lower visual acuity gives a grainier image. Humans can pick out very fine patterns of stripes before the image blurs into solid grey. Testing animals visual acuity involves measuring brain-wave patterns from electrodes implanted into the brain while the animal is shown a striped image. The stripes are continually narrowed until the signal from the animals visual cortex undergoes a characteristic change, showing that it sees a grey image instead of stripes. A less intrusive method involves training the cat to pick a striped card in preference to a solid grey card, the limit of visual acuity is the point where the success rate is 5050 for picking the right card. Cats visual acuity is between 4 and 10 times worse than humans. In medical terms, cats have 2080 vision meaning that what a normally sighted human can see well at 80 feet, a cat can only see in as much detail at 20 feet. Other visual experiments show that cats can distinguish visual textures, for example they can distinguish a triangle of vertical lines from a background of horizontal lines. This helps explain why zebra have vertical stripes to blend with vertical lines of the background (trees, tall grass) - a horizontally striped zebra would stick out like a sore thumb to a lion Cats also see subjective contours. In the diagrams below, when the three-quarter white circles are properly aligned, an optical illusion produces a black square in the middle of them. When they are randomly aligned, there is no square. Cats can discriminate between the visual illusion and the random patterns. Cats supplement their sense of vision with extremely sensitive sense of touch thanks to their whiskers (vibrissae). It is general belief that the large cheek whiskers gauge the width of a hole so a cat can tell if it is large enough to get through. As well as the prominent cheek whiskers, cats have smaller whiskers on the muzzle, whiskers above the eyes and whiskers on their lower legs. A blind cat can feel its way over and around obstacles with great precision. The large number of nerves devoted to these whiskers occupy a disproportionately large area of the cats mental map of its own body (much as the nerves devoted to the hands and fingers dominate in humans). A cats sense of smell is far better than that of humans, but is far less than that of dogs. It is, however, good enough that smells imperceptible to us can confound experiments using cats. Hidden food is not so hidden if you are a cat and can smell it. Cats can detect food going stale (and refuse to eat it) long before we can. Smell is an important sense in animals that mark their territories with urine or faeces or that recognise places and individuals by smell. Cats have excellent hearing and can hear sounds up to about 60,000 Hz while humans (with a few unusual exceptions) can only hear up to bout 20,000 Hz. This means cats can hear the ultrasonic noises made by rats and mice. In addition, they can pinpoint a sound source to within about 8 o thanks to their swivelling ears. Cats have relatively intricate brain wiring for control of their paws compared to dogs. They are surprisingly dextrous when seizing and manipulating objects. This is most obvious in polydactyl (extra-toed) cats as these often their paws to grasp objects. Photographs and X-rays of cats paws in action show several methods of handling an object: it may be pierced with just the claws, held between a claw and pad of the paws, or sometimes held between the paw pads without the use of the claws at all. Cats have some ability to move the digits (toes) of their paws separately, again this is most evident in polydactyl cats. When a cat reaches out to grab an object, it pre-shapes its grip, much as we do, giving it a much better chance of catching and holding the object. Gripping is therefore not simply a mindless reflex action in response to something touching the paw pad. Early Learning and Slowing Seniors Psychologists originally believed that animals like cats and humans are born helpless and dependent and develop the ability to learn later in life. Even helpless human babies are learning the physical rules of the world around and their innate language module is acquiring language. Exhaustive developmental studies in kittens have found that cats also have an innate mental ability to learn that is present from the start. Cat workers often comment that kittens develop a preference for suckling from a particular nipple on their mother. Days old kittens can be trained to preferentially suckle from one of two artificial nipples distinguished by texture, location or smell. Using an artificial mother, consisting of a carpeted surface with two rubber nipples, a 2 day old kitten can learn to distinguish between a nipple that delivers milk, and one that does not, based on its texture alone. Discrimination based on odour is possible just one day later. Kittens in pooled litters can also discriminate between its own mother and other lactating females if it is in a pooled litter and between its mother and an artificial nipple. Despite their mothers protectiveness, kittens have to learn quickly. Orientation develops in the first week. For the first few days, if a kitten is removed from the nest it simply crawls in circles wherever it is. Six day old kittens (i. e. eyes not yet opened) can orient themselves towards the nest in response to the smell of their mother or littermates. By the end of their first week, they have learnt to distinguish by scent the home region of their cage or pen from other parts of the cage. At 2 weeks old, they can orient themselves over a distance of about 3 metres and they begin to explore. Visual cues take over from scent cues at around 3 - 4 weeks. The innate behaviours displayed by kittens are based on inherited patterns, but these behaviours are modified, supplemented and altered, in both the long and short term, by learning. What determines learning ability is not so much innate brainpower as behavioural development i. e. the ability to take in and process information so it does something useful in the real world. Right from birth, animals, are predisposed to find certain things and certain associations important. They are motivated to explore and learn these important things (or at the very least not to shun those things, even if the exploration stage doesnt happen until they are more mature). Early experiences interact with natural instincts and shape the ability to learn later on. Cats also have different personality types which both affect their willingness to learn and which are affected by early experiences in life. Kittens brought up with other animals, a vacuum cleaner, plenty of people and other household objects are more confident in later life than kittens brought up in a quiet home with only one person. Just as you cant teach an old dog new tricks, elderly cats are less able to learn. Many geriatric cats suffer a cognitive dysfunction syndrome similar to Alzheimers disease and often referred to as feline senility. They are easily disoriented, forgetful, they show compulsive behaviours (one of my senile cats had to be confined because she compulsively walked in a more-or-less straight line until she grew tired and simply sat down), sleep erratically, may forget their litter-training or become incontinent. On a molecular level feline senility resembles Alzheimers: plaques of a chemical called beta-amyloid appear in the brain. This interferes with the normal action of neurotransmitters (brain chemicals that relay nerve signals) and is also toxic to nerve cells so that nerves are killed off. Even those cats which dont become senile become slower to learn new things. Studies have found that cats over the age of 10 years are often incapable of learning the basic Pavlovian associations that young cats learn easily. Pavlovian associations are named after the famous Pavlovs dogs experiment where dogs learned to associate a ringing bell with getting a meal and automatically salivated when the bell was rung. Though the older cats were awake and fully alert and their perceptual nerves were supplying the right inputs to their brains, their brains didnt process things as efficiently compared to younger cats. There is a link between learning, brain activity and sleeping. Researchers have found that different patches of the brain can be in different sleep states at the same time. Sleep regulatory biochemicals build up in the brain during wakefulness and help trigger the transition into sleep. They build up faster in parts of the brain that are most active during wakefulness. The harder a brain region works during the day, perhaps learning a task, the harder that brain region has to sleep at night. Cats that are kept in the dark during wakeful hours have to rely heavily on their whiskers to find their way around they have unusually shallow non-REM sleep in the visual cortex, but much deeper non-REM sleep in the part of the cortex dealing with touch. Self-Centred Mental Maps Some of the apparently stupid things that cats do can be explained by how they mentally map out their world. A cats world is three-dimensional (includes shelves, tree branches) and is partly mapped by smells which represent territorial boundaries or signposts. The apparently circuitous route a cat might take to get from A to B is not due to stupidity it is due to the cat avoiding other cats territories or stopping to check out (or deposit) scents which announce its presence, age, health and breeding status to other cats. These are things to be taken into account when understanding how cats map out their world. The simplest type of orientation relies on directly seeing the goal, or a step-by-step route based on landmarks (turn left at the tree, turn right at the fence etc). Simple orientation systems are error-prone - if a landmark is removed, the is animal immediately lost something owners of blind cats are well aware of (although blind cats will attempt to find another landmark so they can reorient themselves). Cats use a mix of these methods and construct mental maps of their surroundings, the more thoroughly they have explored, the better their mental map. Cats can also construct mental maps based on a brief view of relevant features, but these are not remembered for more than a few minutes. Mental maps allow cats to take short cuts, cutting across fields instead of sticking to the edges. If given a choice, cats opt for the shortest route to an out-of-sight goal. If there are several equally short routes, they tend to use the one that starts off by pointing in the direction of the goal - something we ourselves do. Minimising the number of twists and turns in a route affects the choice, but is less important than distance and initial direction. When it comes to finding its way around, a cat learns best by doing, not just by seeing. French comparative psychologists, influenced by the theories of the developmental psychologist Jean Piaget, are interested in how (and whether) various species develop object permanence. Piaget noted that human infants go through various stages of understanding the physical laws of the world. At first, they lose interest when a toy is hidden or taken out of sight and they make little effort to search for it. Once it is out of sight, it has ceased to exist. Older infants will search for something that partially or completely disappears but may not understand where to look. If they see someone hide the object behind a screen, they will not know to look behind the screen but may instead look in a place they previously found it. As they grow older, they will know to look behind the screen and at around 18 months of age they can follow a series of invisible displacements: Invisible displacements are when someone hides the ball in a cup, takes the cup behind the screen and takes the ball out of it, then takes the cup back to the infant and shows that it is empty. The infant reasons that the ball is behind the screen. Piaget termed this Stage 6 object permanence. Object permanence is a useful skill for animals that need to be aware of the most likely location of prey that has gone to ground. If prey becomes temporarily invisible, a cat first searches for it under or behind the place where it disappeared, but if this is unsuccessful it starts searching the nearest available cover. Cats familiar with their territories know and search the most likely hiding places. Cats sometimes appear unable to solve simple invisible displacement using hidden toys because the apparatus used to hide the toy is equally interesting to the cat Even though it knows the toy is under a cloth, many cats will play with the cloth (regarded as a new and therefore more interesting toy) rather than hunt the hidden toy. If you roll a ball under a floor-length drape, many cats get distracted and end up playing with the moving drape because it is a new game. Early experiments suggested cats never reach Stage 6 object permanence. Owners often disputed this finding, based on games with cat toys being lost, hidden or retrieved behind sofas More recent and better designed studies show that they do reach Stage 6. The cats were tested in their familiar home surroundings and the screens were left around for a week in advance so the cat got used to them and also so they learnt there were no toys hidden behind them. The cats were first taught that whenever they touched their noses to a particular toy they got a food reward. For the actual test, a cat was lightly restrained by its owner and two screens were positioned in front of it. In full view of the cat, the experimenter put the toy in a cup, secretly removed the toy behind one of the screens, and then placed the empty cup in front of the cat. The at was released and, in nearly every trial, went straight behind the screen where the toy had been hidden. The screens were moved from trial to trial and were replaced with new screens of a different appearance, but the cats still got the right answer, proving that they had not just learned a local rule but had generalised the solution. Objects do not simply cease to exist and if the object was in the cup before it went behind the screen, but was not in the cup when it emerged again, then the object must logically be behind the screen. In another test, a cat watched food being hidden in a cup, and the cup was then hidden in turn under three covers, after which the empty cup was shown to the cat. To eliminate scents, the food was not actually deposited under the last cover, but was palmed by the researcher. In one test as soon as the cup was removed from under the final cover and shown to be empty, the cat hurried to this cover (not to the researchers hand). It persistently pushed back the cover until the place where the food should have been was entirely revealed. Not finding any food, it pawed at the cover and tried to push its face underneath for several more minutes. When confronted by prey that has gone to ground, it pays to be persistent (within reason). In a more complex series of experiments, all sorts of disorienting visual tricks were played between the time the cats saw a toy hidden behind one of several identical-looking screens and the time they were allowed to search for it. In one test, the toy was first placed behind the rightmost of 3 screens. The cats view was momentarily blocked and all the screens were slid over to the right by a distance exactly equal to the spacing between them. In another test, the cat looked into the experiment chamber from the doorway and after the toy was hidden, the cats view was blocked while he entire room (walls and all) was shifted to the right. In spite of these tricks, when the cats were released to look for the toy, they found it by using an absolute sense of position (a course and bearing from its own position) rather than a relative one. They did not look for it behind what was now the rightmost screen, instead they looked behind the screen that now occupied the precise spot in space that the rightmost screen had previously occupied when the toy was hidden. A cats sense of space is egocentric - they remembered where the toy was placed relative to their own fixed position in space, and not by the toys position relative to a landmark. When the experiment was set up to make egocentric spatial reasoning impossible, the cats were forced to orient themselves using landmarks. From a central doorway, the cats observed the toy being hidden. However, they could only enter the room by taking a detour through an L-shaped tunnel, entering the room through a door to either the left or the right of the one they had watched from. Unable to use an absolute sense of position. These cats successfully located the toy using landmarks. If the egocentric cues and the landmark cues conflicted, the cats trusted to their own cat-centred co-ordinates. Cats form a mental map of their environment, but instead of mapping landmarks (the church is 300 ft to the left of the shop, the shop is a mile north of the farm) a cats mental map has the cat in the middle and everything else is relative to the cats position. This explains why cats do some apparently stupid things, such as failing to cotton on to a moved litter tray even if they watched you move the litter tray a moment ago, and why they are such creatures of habit. It takes time to adjust the egocentric co-ordinate system, hence moving the litter tray should be done by shifting it a foot or so each day and moving the feeding station should be done by establishing two feeding stations and only removing the old one when the cat has got a co-ordinates fix on the new one. Its not that cats are stupid, its just that their internal maps is different from ours. The Feline Time-Space Continuum Many species have specialised modules of the brain for certain tasks. Species which cache nuts and seeds for the winter have a phenomenal spatial memory (and a correspondingly large hippocampus region of the brain). London taxi-drivers who have to remember lots of routes and street locations also tend to have a relatively large hippocampus. Humans have a highly developed language module and human infants can acquire language, complete with rules of grammar, just by listening to it. Border Collies instinctively herd things. Experiments to assess animal intelligence often overlook or dismiss them innate or instinctive skills as being unrelated to intelligence. Instinctive skills may still require a huge amount of brainpower by hardwiring them as instincts, the animal is spared the overhead of having to learn them from scratch, but it must still hone these skills. Cats instinctively hunt things. Even if they dont hunt prey, they show hunting behaviour when playing with toys, playing with other cats or playing with owners. Hunting involves knowing where to find prey, following the motion of fast-moving prey and co-ordinating the motion of paws and jaws to seize the prey. As kittens, a lot of feline play is geared to honing these instincts. The basic hunting skills are hard-wired into the cats brain. Even if a cat has never hunted, the pounce-and-bite behaviour can be triggered by stimulating the appropriate part of the brain with an electrode inserted into it (like the poor feline robots described by Fernand Mery). The behaviour is automatic and even if the cat is not hungry it will still react to the stimulus whether it is an electrode or the sight and sound of prey. In the wild, a cat cannot afford to pass up a chance to catch a meal (in the wild, a cat is rarely so well fed it cant manage another meal). Many owners have seen their cats watching nature programs on TV. Most cats quickly put the TV into the same mental category as a window - they can see and hear the animals, but cant reach them. After one or two investigations behind the TV or the speakers, they learn that the animals stay inside the box. After that they dont bother checking for escaped TV animals again, or at least dont expect to find anything if they do check - when you are a cat, it cant hurt to be absolutely sure there isnt a snack-sized wildebeest behind the TV The interesting thing is cats recognise TV images of wildebeest as being potential prey. The secret is they recognise how animals move. Cats can tell the difference between the motion of a living thing such as a mouse or a TV image of a wildebeest and the motion of an inanimate object such as a blown leaf or a rolled ball. In one experiment, cats were shown moving images on two computer screens. One image contained 14 dots that represented the outline of a walking or running cat. The other contained 14 randomly moving dots. The cats consistently distinguished between the interesting animal motion dots (animals food potential) and the less interesting random dots. However, if the animal motion computer screen was turned upside down, the cats could no longer distinguish it from the random motion screen. To a cat, animals running upside down make no logical sense. Modern AI programmes have problems recognising animal motion dots even when they are the right way up. A famous specialised feline instinct is that of landing on all four feet, known as the self-righting reaction. In experiments, young kittens were dropped 40 cm (16 inches) onto a cushioned surface. At 4 weeks old, they lacked the ability to right themselves. Between 4 and 6 weeks old their self-righting ability developed and improved until at 6 weeks old they consistently landed on their feet. Though the instinct is hard-wired into the cats brain, it has to be honed and the usual time for honing it is when curious kittens fall out of trees or off of furniture. In cats with normal motor abilities, but certain types of brain damage, the self-righting reaction is lost and seemingly cannot be learnt from scratch (noted through observations of pet cats). Adult cats have been trained to demonstrate their self-righting ability for time-lapse photography. Having worked out the distance they are falling (the same every time), some cats became lazy and left self-righting to the last moment These lazy cats demonstrate that cats have a remarkable sense of time as we will see later on. Some animals, such as the seed-hiding birds and fruit-eating monkeys, have excellent spatial intelligence. They can find their way to a series of fixed sites (caches or trees) using the safest or most efficient routes. In addition, some animals optimise their routes so they visit the richest food sites first. Cats are opportunist hunters and do not follow such carefully planned routes. They probably dont decide in advance what sort of prey they are going to hunt. Of those cats that rely on hunting, for example farm or feral cats, they spend only a few hours each day hunting and the typical hunting trip is less than 30 minutes. This was reflected in laboratory experiments which show that learning certain kinds of spatial relationships does not come naturally to most cats due to the egocentric mental maps (and the use of scent markers on vertical surfaces). Though complex spatial relationships may not come naturally to cats, remembering a simple location does. Having learned that prey (or cat food) is usually to be found in a particular location, cats will return to the location. Moreover, they associate the availability of food with a time of day or time interval: cats are very good at time calculations as the owners of furry feline alarm clocks with no snooze button can confirm. Cats appear to calculate how much time to invest in hunting and can discriminate time intervals with an impressive degree of precision. For a cat, the time interval between hunting trips and the energy expended on a hunting trip are more important than the spatial relationship between areas where food is obtained. Cats can tell the difference between a sound that lasts 4 seconds from one that lasts 5 seconds and can learn to delay their response to a stimulus by several seconds, down to an accuracy of one second. This means they have an internal clock, with a one second accuracy, that can be used to time both external and internal events. In one experiment, cats were placed in cages for either 5 seconds or 20 seconds. When released, they were rewarded with a food treat that would always be hidden in the left-hand feeder if they had been in the cage for 20 seconds and in the right-hand feeder if they had been in the cage for 5 seconds. If the cat went to the wrong feeder, it was counted as an error. After training 14 cats, using 400 - 1000 repetitions of the drill each (depending on the cat), all 14 cats could pick the correct feeder more than 80 of the time. The researchers then shortened the 20 second trials to see if the cats could still tell the difference between a long wait and a short wait. 7 of the cats could discriminate a 5 second interval from an 8 second interval. In another experiment cats were trained to press a bar a number of times to open a food tray having gained access, they could eat as much as they wanted at that sitting. At first it took 40 presses to gain access to the food. As the number of bar presses required for the food tray to open was increased (up to 2560), the cats responded by eating fewer meals each day, but eating more at each sitting. The cats were not counting the presses (well look at number sense later on), they simply continued pressing the bar until the food tray opened. For a cat to press a bar 2560 times shows a remarkable level of patience and persistence. The trade off was to expend less effort but more often, or expend more effort but less frequently. Researchers then varied the number of bar presses from one meal to the next, the cats calculated the average price per meal. They amount they ate at a given meal was related to the average number of times they had pressed the bar in the course of a whole day or over a period of several days, not to the number of times they had pressed it for that particular meal. According to psychology lecturer Britta Osthaus at the University of Exeter, cats do not understand cause and effect. She expert attached fish and biscuit treats to one end of a piece of string and placed these under a plastic screen to see if the cats were able to work out that pulling on the string would pull the treat closer. The cats were tested using a single baited string, two parallel strings where only one was baited, and two crossed strings where only one was baited. All cats succeeded at pulling a single string to obtain a treat (93 of the time) showing they were able to learn the connection between the string and the treat, but none of the cats consistently chose the correct string when two strings were parallel. When tested with two crossed strings one cat chose the wrong string consistently and all of the others performed at chance level. According to Osthaus, dogs were able to solve the parallel string test, but cats werent. This test was flawed. Firstly, cats are less food motivated as dogs, and are as likely to be interested in the string as a toy as in achieving a treat. Secondly, the comparison with dogs was also incorrect as another paper, co-authored by Osthaus - if the strings were placed at an angle or were crossed, the dogs tended to paw or mouth at the location closest in line with the treat. In other words, both cats and dogs understood the means-end connections involving strings, but they were both unable to understand crossed strings - something very different from failing to understand cause and effect. Dogs evolved as pack hunters that may select a single animals from a herd - not dissimilar from selecting a string that will give a food-reward. Cats evolved to stalk single prey rather than making choices in that way. If a cat has previously found a mouse at a certain mouse-hole, it makes sense for the cat to check that empty mouse-hole again as other mice may be there. In this way of thinking, it makes sense for the cat to check the empty string that previously had a food payoff. Dogs make choices when pursuing prey, cats investigate all available bolt-holes. If you design a test that favours the dogs natural behaviour and view of the world then the dog will appear to perform better. Pet cats have learnt how to open doors using door-knobs and experimental cats have learnt to dispense food using a lever both instances of cause and effect. When cats do deign to co-operate on traditional animal intelligence and learning tests, they perform quite well. As cat owners well know, cats clearly indicate when they are bored of the game, which means a lot of patience is needed on the part of the testers. Cats do not like frustration and will often give up or select random answers when faced with situations where there is no clear path to a pay-off. In the wild, a cat frustrated by elusive prey will eventually go and hunt something easier instead it makes a trade-off between time and energy spent and the likelihood of a worthwhile meal. In intelligence testing, cats learn to learn when rewarded for their efforts, but they will learn to not bother learning when faced with problems with unclear goals and no guarantee of a reward. L. T. Hobhouses experiments consisted of simple puzzles that his animals had to solve to get a food reward, though he noted that the cats innate nature made it a difficult subject. My first experiment was with my cat Tim, a small black tom, rather more than a year old. Tim is a sociable creature, who follows his friends about in the half dog-like way that some cats have, but as a psychologist he has two great defects. His attention is of the most fickle order, and what is even worse, he gets his meals at the most irregular times, and by methods known only to himself. It is therefore impossible to say beforehand whether he will take any sustained interest in the proceedings at all. Here is one of Hobhouses experiments: A piece of meat was placed on a card to which a string was tied, and then placed on a shelf beyond reach of the animal with the string dangling down. I first tried this with Tim, thinking that a young cat would very likely pull the string in play. I was surprised to find that he took no notice of it. I showed him seven times, pulling the string down before his eyes, and letting him get the meat. Neither this, nor a series of trials in which the card was placed on the table barely out of the cats reach, had the slightest effect. The kitten once grabbed the string as I was arranging the card, probably in play, and brought the card down without the meat. For the rest, he either made no attempt at all, or tried to claw at the meat directly. About a fortnight afterwards I began a long series of trials in which the string was tied to a chair leg to make it more conspicuous. Fourteen trials gave no result. Next day, eight trials passed without result, but at the ninth, the cat bit slightly at the string close by my fingers as I adjusted it, and as soon as I had got it right, pawed the string down. The biting was doubtless due to the string being slightly smeared with fish, but the effect was apparently to call the cats attention to the string for the first time in all this long series. It is clear that, in pawing it, his aim was to get the fish on the table. If he had merely been attracted by the smear on the string, he would have used his mouth. At the next trial, he sat still for a while, and then pawed the string again. At the next, he took to washing himself, and I gave up for a time but on replacing the string I saw him watching me, and he pulled it down at once. In the next trial he did the same. Next day he appeared to have forgotten, but walked under the string and knocked it down with his tail. At the second trial, he slightly brushed against the string, but walked away. I had to rearrange it. He watched me doing so, and pawed it down at once. He then pulled it five times running without hesitation. The cat, it seemed, treated the experiment as a game (although Hobhouse did not actually say this). There are reasons for its repeated failure to understand what was expected of it. It might have had difficulty recognizing the relevance of the thin string, particularly as cats are long-sighted and it might not have been able to see the string properly. Alternatively, the first time it pulled the card down there was no reward and the cat immediately lost interest it was much more interested in the smell of fish later on. On a later occasion, the reward of fish came at the first attempt and the cat was then quick to learn the trick. Hobhouse had discovered how easily cats are demotivated. In one set of experiments cats are presented with a pair of mismatched wooden figures which might differ in shape, size or colour e. g. a black square to the left of a white circle. The cat chooses one or other object by nosing it and every time he picks, for example, the black square on the left hand side, he is rewarded with food. Once the cat consistently picks the black square, the experimenters randomly switch the black square to the left or right of the white circle. After much patient repetition, the cats get the hang of picking the black square rather than whatever shape is on the left hand side (the success criteria is picking the correct shape 80 of the time since most cats occasionally check out the other shape, just in case). Later the white circle might be exchanged for a different shape such as a white triangle, or even a white square, and the cat learns to pick the original black square no matter what the other shape is. Similar object discrimination tasks have been used to assess other aspects of feline intelligence, not just whether it can tell the difference between shapes, colours and textures. Having learnt the correct solution to one such object discrimination problem, cats can learn to generalise from the experience. They catch on faster to similar object discrimination problems. To begin with, each new pair of objects requires dozens of repetitions before cats hit the magical 80 mark. After mastering about 60 different object discrimination problems, many cats will hit the 80 mark after only 10 trials. In other words, the cats have learnt that the rules of the game are to work out which of 2 objects results in a reward. Cats can extrapolate from right answers, but are not so good at extrapolating from wrong answers and end up becoming discouraged, bored and unco-operative if they keep getting a test wrong. If the test cat is lucky enough to get the right answer and its reward on the first try, he masters the problem much faster than if he picks the wrong, unrewarded answer the first try. This is not due to lack of intelligence, but is to do with a hunting animals innate behaviour. If a mouse is not found at the first location a cat visits, the cat does not automatically visit the second location - cats are opportunist hunters and do not follow fixed search patterns. By contrast, foraging animals visit a fixed set of likely food sources, starting with the most likely food source first. Cats wont tolerate frustrating situations for long and quickly give up or become indifferent when there is no clear path to a reward. So they have a harder time with a problem where they have to learn to pick an object on a given side, either the left or right, depending on which of two possible pairs of identical objects (e. g. 2 black squares versus 2 white circles) is presented. This problem has no equivalent in the cats natural world, so they have difficulty learning what is expected of them. Many cats eventually learn to solve tough problems like this, but their performance is generally only better than chance. They also have more problems extrapolating from right answers when presented with a new tough test. Cats that are given a mix of simple and tough problems catch on faster to the tough problems than do cats who are given a straight course of nothing but the tough problems. One cat who had only ever been presented with tough hard problems, never learnt to master a simple blackwhite discrimination task despite 600 trials. With no equivalent challenge in nature, cats presented with only tough tests become demotivated and appear content to get an occasional handout when they choose the right answer by chance. In certain types of test, intelligent cats are content to underachieve - a problem with the design of the test, not with the cats intelligence FELINE INTELLIGENCE PAGE 2