Course P1.1 – General Foundations Biological Bases of Cognition (Cognition in Chimpanzees) Dr Stephen Walker December 16th 2004 Cognitive processes in animals, especially primates. Whereas ethologists and behaviourists used to explain animal behaviour in terms of reflexes, it is common now to talk of animal cognition. The great apes are more closely related to the human species than other animals, and might thus be expected to have more human-like cognition. But hard evidence for this is weak, and some authors reject this idea (Macphail, 1987; Heyes, 1998). Primate Cognitive Superiority? • An extreme case of this notion was the expectation that, with sufficient training, infant apes would develop linguistic competence. (E.g. Gardener and Gardener, 1969). • There is now a wide consensus that what chimpanzees achieve, even after years of training, merely emphasizes the importance of inherited human specialized capacities. Human-like capacities other than language • Piagetian tests suggest that ape infants go through similar stages to human infants at least during the sensori-motor period (1st year). • Imitation and social learning may be primate characteristics. • Tool using occurs in some populations • Memory for recent events in primates may be very extensive (Menzel, 1973). Mental attribution and “Theory of Mind” • Self-recognition in mirrors seems to only occur in apes. • It is suggested that this indicates a broader capacity for introspection and for attributing mental states to other individuals (Gallup et al, 1995; Boysen and Himes, 1999; Call, 2001; Tomasello, 2000). • Povinelli (1993) reviews this suggestion, but others such as Heyes (1998) and Povinelli et al. (2000) are sceptical even about self-recognition. Jolly (1972) cover 2nd Edition is Jolly (1985) Taxonomy of Primates (an Order of Mammals: p.5 of handout There are two sub-orders of the order Primates. One sub-order includes humans, apes and monkeys, and the other is for Prosimians, and includes the lemurs of Madagascar, lorises (e.g. bushbabies) and tarsiers. PROSIMII (The older of the two suborders of Primates) Prosimians: = the lemurs of Madagascar, lorises (e.g. bushbabies) and tarsiers. Anthropoidia ANTHROPOIDEA (A suborder of Primates) This includes 3 superfamilies, the superfamily of humans and apes and two superfamilies of monkeys: Humans and Apes (Hominoidea). Includes extinct human species (‘hominids’), modern Homo sapiens and the apes. “Great apes” are 2 species of chimpanzee, the orangutan and the gorilla, and “Lesser apes” are 7 species of gibbon. Old-world monkeys: (Cercopithecoidea or Catarrhines) = dozens of species e.g. rhesus and other macaques, vervets and baboons. New-world monkeys: (Ceboidea or Platyrrines) = dozens of species e.g. cebus, squirrel, spider and owl monkeys and marmosets. Similarities in primate lifespans Table of Primate Life-Spans (After Jolly, 1972: p. 6 of handout) Life spans Species CEBUS RHESUS GIBBON ORANG CHIMP GORILLA Homo (New (Old (Lesser World World Ape) Monkey) Monkey) (Great Ape) (Great Ape) (Great Ape) Sapiens sapiens Days Gestation 180 168 210 275 225 265 266 Total yrs 30+ 28+ 29+ 30+ 40+ 35+ 70+ Sub Adult yrs 4.0 7.5 8.5 10.5 10.0 11.0 20? Infancy yrs 0.5 1.5 2.0 3.5 3.0 3? 6? % 13% Subadult 27% 29% 35% 25% 31% 29% % Infancy 5% 7% 12% 8% 9% 9% 2% Similarities in brain anatomy T.H. Huxley (1863, 1874) “So far as cerebral structure goes therefore, it is clear that man differs less from the Chimpanzee or the Orang, than these do even from the monkeys, and that the difference between the brains of the Chimpanzee and of Man is almost insignificant, when compared with that between the Chimpanzee brain and that of a Lemur. “(Darwin, 1874/1901, p. 312) ‘Every principal gyrus and sulcus of a chimpanzee’s brain is clearly represented in that of a man’. Human brain Chimpanzee brain The chimpanzee brain is only about a third the size of a typical human brain, but superficially looks similar Mammal and primate brains Huxley’s comparisons “So far as cerebral structure goes therefore, it is clear that man differs less from the Chimpanzee or the Orang, than these do even from the monkeys, and that the difference between the brains of the Chimpanzee and of Man is almost insignificant, when compared with that between the Chimpanzee brain and that of a Lemur. “(Darwin, 1874/1901, p. 312) Semendeferi abstract Asymmetry in Broca’s Area (Cantalupo and Hoplins, 2001) Similarities in DNA Diamond (1992) 3rd Chimpanzee Human DNA is 98.4% the same as that of the chimpanzee mouse Chimp genome dec 10 2003 DNA similarities • • • • • • • • human to yeast about 30% Main source: human to worm about 40% http://genome.pfizer.com/ human to fruit fly about 60% human to mouse about 90% human to rhesus monkey about 93% human to chimp about 98.4% human to human about 99.9% identical twins, 100% identical Tree from enard functional genomics Common ancestor Similarities in facial expression Many expressions mouth face Emotional expression “tense-mouth face” Emotional expression 2 Emotional expression 3 “Open mouth threat” Open mouth (Facial expressions taken from Jolly, 1972) Preadaptations for tool use Stick play overarm Kohler, 1925: Gleitman 1999 p. 159; 2004, p. 158 Climbing poles menzel Sticks as weapons Tool use in wild chimpanzees • Since 1987 in Guinea in West Africa, observations have been being made in the centre of free-range area, where experimenters provide stones and nuts. Infants under 3.5 years old do not crack nuts themselves • Inoue-Nakamura, N, & Matsuzawa, T (1997) Development of stone tool use by wild chimpanzees (Pan troglodytes). Journal of Comparative Psychology, Vol.111, No.2, Pp.159-173. Use of tools African Oil Palm Has fruits about the size of a plum, which occur in very large bunches weighing up to 20 kilos. Tool use in wild chimpanzees Nut cracking consists of the following actions: • • • • • (a) picking up a nut (b) putting it on an anvil stone (c) holding a hammer stone (d) hitting the nut with the hammer stone (e) picking up and eating the nut kernel. Tools (Bossou) Tool use in wild chimpanzees • The individual actions of ‘Take’, ‘put’ ‘hold’, ‘hit’ and eat, had all been performed by 1.5 yrs • At 2.5 they often put a nut on a stone, hit it with the back of their hand, then picked up a kernel from somewhere else or scrounged a kernel from their mothers • Holding the hammer was the a difficult part – chimps never hit nut with the hammer stone until the last stage Tool use in wild chimpanzees Discussion • “True imitation cannot explain the results of the present study” • As the present results suggest, they learned the general functional relations of stones and nuts • and also learned the goals obtained by the demonstrator • This learning process might be called emulation Tools group at bossou Termite fishing Home rearing studies Kelloggs (1933) Arm strength Revolver Spoon Gua Gua several Ready for bed tickling Walking together image Walking together image and text Primate Cognitive Superiority? • An extreme case of this notion was the expectation that, with sufficient training, infant apes would develop linguistic competence. (E.g. Gardner and Gardner, 1969). • There is now a wide consensus that what chimpanzees achieve, even after years of training, merely emphasizes the importance of inherited human specialized capacities. Attempts at Language Training Method Names of chimps Names of psychologists Gardner and Gardner (1969) SavageRumbaugh Terrace et al, 1979 American Sign Language (ASL) Washoe, Austin & Sherman Kanzi Nim Chimpsky Plastic tokens Sarah (& others) Premack (1971, ‘76 & ‘86) “Lexigrams”: visual symbols on a screen Austin & Sherman, + others Greenfield and SavageRumbaugh (1993) Pause Vicki imitating Vicki (Hayes & Hayes, 1951) Vicki (Hayes & Hayes, 1951) Vicki (Hayes & Hayes, 1951) • Vicki died when 7 • Lots of imitation, throws and catches balls, cuts paper with scissors, opens doors, flips light switches • At 5.5 spontaneous sorting of e.g. nuts bolts screws and washers without error • Conclusion was that Vicki had rudimentary higher mental functions • But she had only 4 “spoken words” mama, papa up and cup plus 3 spontaneous sounds pause Nim 1 p. 7 Terrace, H.S. (1979/1980) Nim. London:Eyre Methuen. Terrace, H.S., Pettito, L.A., Sanders, R.J. and Bever, T.G. (1979) Can an ape create a sentence? Science, 206, 891-902. The project lasted 4 years and involved 60 teachers, mostly volunteers. Another group of about 40 volunteers tabulated and analyzed data from daily records and videotapes. In the Science paper more than 19,000 “multi-sign utterances” were analyzed for syntactic and semantic regularities. Nim p. 393 hug (1999, not in 2004)_ Nim p. 393 apple (1999, not in 2004) Nim with cat Nim’s happy face Washing up Nim 1 p. 7 Terrace, H.S. (1979/1980) Nim. London:Eyre Methuen. Terrace, H.S., Pettito, L.A., Sanders, R.J. and Bever, T.G. (1979) Can an ape create a sentence? Science, 206, 891-902. The project lasted 4 years and involved 60 teachers, mostly volunteers. Another group of about 40 volunteers tabulated and analyzed data from daily records and videotapes. In the Science paper more than 19,000 “multi-sign utterances” were analyzed for syntactic and semantic regularities. Nim 2 p. 7 There were some regularities, but videotape analyses showed that most of Nim’s utterances were prompted by his teacher’s prior utterances (signs in American Sign Language). Nim interrupted his teachers to a much larger extent than a child interrupts an adult’s speech. Nim 3 p. 7 Typical two-sign combinations were — “play me” (375) “tickle me” (316) “hug Nim” (106) “tickle Nim” (107) ----“more eat” (287) -----“banana Nim” (73) “in pants” (70) Nim 4 p. 7 Typical three-sign combinations were — “play me Nim” (81) “eat me Nim” (48) “eat Nim eat” (46) “tickle me Nim” (44) “grape eat Nim” (37) “banana Nim eat” (33) “Nim me eat” (27) “banana eat Nim (26) “eat me eat” (22) Typical four-sign combinations were — “eat drink eat drink” (15) “eat Nim eat Nim” (7) “banana Nim banana Nim” (5) “drink Nim drink NIm” (5) “banana eat me Nim” (4) “banana me eat banana” (4) “banana me Nim me” (4) “grape eat Nim eat” (4) “Nim eat Nim eat” “play me Nim play” “drink eat drink eat” (3) “drink eat me Nim” (3) Nim 5 p. 7 Washoe 2000 • Jensvold, M. L. A., & Gardner, R. A. (2000). Interactive use of sign language by cross-fostered chimpanzees (Pan troglodytes). Journal of Comparative Psychology, 114(4), 335-346. • NB. an ’X’ following a sign indicates an immediate repetition of the sign; a ‘?’ indicates an ASL version of questioning inflection, and a ‘/’ indicates the ASL inflection corresponding to the end of an utterance. Washoe 2000 • • • • • • • • • Trial #3 (page 337) Example 1 in lecture 1:04:35 Washoe: ME GIMMEX/ 1:04:40 Probe 1: questioning expression 1:04:41 Washoe GIMME/ 1:04:49 Probe 2 WHAT?/ 1:04:51 Washoe MEX GIMMEX/ 1:04:54 Probe 3 NOT UNDERSTAND? 1:04:56 Washoe FOOD GIMME/ End of trial Washoe 2000 - 2 • • • • • • • • • Trial #5 (page 338) Example 2 in lecture 0:08:46 Washoe: FRUIT GIMMEX/ 0:08:49 Probe 1: WHO FUNNY? 0:08:51 Washoe ROGER/ 0:08:54 Probe 2 WHERE CAT?/ 0:08:56 Washoe ROGER GIMMEX/ 0:09:03 Probe 3 WHERE CAT? 0:09:05 Washoe GIMMEX/ End of trial “Conversations” 2002 • Bodamer, M. D., & Gardner, R. A. (2002). How cross-fostered chimpanzees (Pan troglodytes) initiate and maintain conversations. Journal of Comparative Psychology, 116(1), 12-26 • NB. an ’X’ following a sign indicates an immediate repetition of the sign; a ‘?’ indicates an ASL version of questioning inflection, and a ‘/’ indicates the ASL inflection corresponding to the end of an utterance. “Conversations” 2002 - 2 • • • • • • • • Tatu: PERSON TIME/ Probe 1: WHAT?/ Tatu: FOOD TIME FOOD TATU/ 2. “On topic”. Example Tatu: TIME/ Probe 2: WHAT TIME?/ Tatu: FOOD TIME FOOD/ Mental attribution and “Theory of Mind” • Self-recognition in mirrors seems to only occur in apes. • It is suggested that this indicates a broader capacity for introspection and for attributing mental states to other individuals (Gallup et al, 1995; Boysen and Himes, 1999). • Povinelli (1993) reviews this suggestion, but others such as Heyes (1998) are sceptical even about self-recognition. Self recognition (?) in mirrors Mirror tongue Mirror 3 Povinelli 97 abstract Povinelli et al (1997) mirror theory Povinelli et al (1997) mirror data Imitation (?) Cultures? Whiten, A., Goodall, J., McGrew, W. C., Nishida, T., Reynolds, V., Sugiyama, Y., Tutin, C. E. G., Wrangham, R. W., & Boesch, C. (1999). Cultures in chimpanzees. Nature, 399(6737), 682-685 Conclusion p.4 of handout • Many aspects of human cognition are unique. • The capacity for language is one of the most important. • Other aspects of human cognition, such as object recognition, may be found in many other species. • Many authors believe that the great apes, particularly chimpanzees, exhibit more human-like cognition particularly in the area of social learning. Intranet Look under timetable But none of the illustrations from any of the Gleitman texts, and very few from elsewhere are included for reasons of copyright. Online handouts