School of Psychology, Birkbeck College

Course PSYC044U (Psychobiology II.) WEEK 10
April 26th 2007

gifThis is just the first 6 pages of the longer paper handout. Web versions of the other pages in the paper handout are accessible from the side index. If you need to print out the handout, then all the pages are in this 'pdf' file, but this is quite large and may be difficult to download over a telephone modem.



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Essay (no 8 on the March 15th list)

“Apes cannot be taught language, but there is evidence that they have special abilities in the areas of social learning, imitation, and self- recognition.” Discuss.



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Notes (see also the Easter Handout for Summer-Term Lectures)

A quotation —

“A third hypothesis proposes that there are, in fact, neither quantitative nor qualitative differences among the intellects of non-human vertebrates. It is argued that this null hypothesis is currently to be preferred, and that man's intellectual superiority may be due solely to our possession of a species -specific language- acquisition device” (Macphail, 1985; p.37; see also Macphail, 1996 and Macphail and Bolhuis, 2001).


  • Macphail is an example of those who disagree that primates (other than humans) have more than co-incidental cognitive advantages over other species. He supports a ‘null- hypothesis’ of equal intelligence (assessed in terms of associative learning) across all vertebrate species. Others such as Herman (see Shyan and Herman, 1987) would suggest that there are species differences in cognitive ability, but that certain non- primate species (dolphins, or other large-brained mammals) demonstrate primate levels of performance on complex tasks. Macphail (1985, 1998) and Heyes (1998) take the view that there essentially no differences betewen the cognitive capacities of different vertebrates species, as the above quotation suggests. Slotnick (2001) has argued that small-brained animals are often as good or better that large-brained animals at solving complex associative problems and Giurfa et al. (2001) have data suggesting that honey bees are able to learn “sameness” and “difference” concepts which had previously thought to be a primate speciality (e.g. Thompson and Oden, 2000)

  • An opposite view is that because primates are biologically more similar to people than other species, cognitive processes in primates (especially in our closest living relatives, the great apes) will be noticeably human-like, and distinguishable, quantitatively or quantitatively, from those of non-primate species. It is clearly necessary to assess the behavioural evidence very carefully in order to evaluate the soundness of this assumption. Slotnick (2001) has argued that small-brained animals are often as good or better that large-brained animals at solving complex associative problems and Giurfa et al. (2001) have data suggesting that honey bees are able to learn “sameness” and “difference” concepts which had previously thought to be a primate speciality (e.g. Thompson and Oden, 2000).

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  • An extreme case of the notion of primate cognitive superiority was the expectation that, with a sufficiently favorable training environment, infant apes might develop linguistic competence (e.g. Premack, 1976). Studies which attempted to train apes in language-like skills are reviewed in Walker (1985) and Walker (1987). (See page 3 for a summary table).
  • There is now a general consensus that some or other of the cognitive processes necessary for linguistic communication is innately and exclusively human (Hauser et al., 2002; Elman, 2005; Rivas, 2005; Pinker & Jackendoff, 2005).
  • In particular Premack (1986) said he could find no trace of properly linguistic abilities in chimpanzees after many years of attempting to, and concluded that the human species possesses a number of ‘hard-wired’ cognitive specializations, including that for recursive syntax.
  • However Premack (1986) continued to believe that non-human primate cognition is distinctive. In 1983 he proposed that only primates have an ‘abstract code’ for higher-order representations of object properties. In 1986 Premack suggested that primates were distinctive in the understanding of the semantic categories of the agent, recipient and patient of an action.
  • (See page 7 for a definition of these terms, and Crockford et al., 2004, Pika & Mitani, 2006, Wich & de Vries, 2006 and Hopkins et al., 2007 for other primate abilities with some relation to verbal and gestural communication.)

  • Although evidence for language-like communication in apes remains weak (despite Savage-Rumbaugh et al 1986 and Greenfield and Savage-Rumbaugh, 1993; Bodamer and Gardner, 2002; Jensvold and Gardner, 2000; see Rivas, 2005), experimental studies of primate cognition have implied that apes, and to a lesser extent, monkeys, are at least quantitatively superior to other species at various kinds of reasoning task (e.g. Gillan et al 1981; Menzel et al 1985; Boysen and Himes, 1999; Call, 2001; Tomassello, 2000; Boesch, 2002; Brauer et al., 2005; Melis et al., 2006: see also week 11).

  • Many authors going back to Jolly (1966) and Humphrey (1976) have supposed that primate intelligence is related to the complexity of primate social interactions. Recent examples include Crockford et al., (2004), Perry et al., (2004), Tomasello et al. (2005) and Pika and Mitani (2006). “Theory of Mind” hypotheses suppose that only some species have a functional concept of “self” (Gallup, 1970) or that only particular species (usually only the great apes) are able to make inferences or assumptions about the goals and intentions of conspecifics or human experimenters (Premack and Woodruff, 1978; Whiten and Byrne, 1997). This has recently attract extra interest because of the hypothesis that human autism is characterised by a lack of this capacity (e.g. Leslie, 1987). The social cognitive features of “shared-reference” (or “shared-attention”) and “proto-declarative” communicative acts have been proposed as important pre-conditions both for the development of a “theory of mind” and for the development of human language (Baron-Cohen, 1992; Savage-Rumbaugh et al, 1983; Tomasello, 2000; Suddendorf and Whiten, 2001; Elman, 2005: see Week 11)

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Further notes on species differences in cognition

1. Global versus local adaptations (Davey, 1989)

Macphail’s “Null hypothesis” corresponds to an emphasis on “global adaptations” (see sheet 5 of the week 3 handout). It is certainly the case that behavioural processes such as habituation are very widespread across species, but there is also evidence for species specific specializations such as visual recognition and memory for food locations as discussed in week 8 and week 9.

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2. The issue of brain size (page 9 in Pearce, 1997)

There are extremely large differences between species both in absolute size of the brain, and in the size of the brain in relation to body-weight. Although the relation between brain-size and brain function is to some extent indirect, one of the reasons for assuming that primate cognitive abilities may differ from those of the average mammal is that primates in general have above-average brain weights for their body size. (see page 8 of handout for replotted data and Ponting & Jackson, 2005, Evans et al., 2006 and Tang, 2006 for recent studies of the genetic mechanisms behind the increases in brain size in primates and in humans in particular.)

3. Specializations in brain function.

Most primate species share with humans the specialization in foveal colour vision, which is not used by other mammals, and elaborate social interactions exhibited over a long life-span. In terms of both ecological and anatomical specializations therefore, we would expect to find something in common between human cognition and cognition in primates (e.g. Barton, 1998; Regan et al., 2002). There is increasing evidence, in part due to brain-imaging studies in humans, that there is detailed correspondence between localization of brain function in humans and other primates (e.g. Ungerlieder, et al, 1998; Courtney et al, 1998; Rizzolati et al, 1996; Cantelupo and Hopkins, 2001; Miller et al., 2002; Semendeferi et al., 2002; Bush and Allman, 2004; Schenker et al., 2005; Sherwood et al., 2006; Tsao et al., 2006).

However, a recently emerging field of research is the genetic and neural aspects of brain development and function which are uniquely human (Enard et al., 2002a and 2002b; Elson et al., 2001; Buxhoeveden et al., 2001; Rilling and Seligman, 2002; Preuss et al., 2004; Pollard et al., 2006)

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Summary of Attempts at “Language” Training
References Name(s) of animals Mode of Communication Training
Kellogg and Kellogg (1933)GuaVocalHome rearing
Hayes and Hayes (e.g. 1951) Vicki Vocal Home rearing, moulding of lip position
Gardner and Gardner (e.g. 1969). Jensvold & Gardner (2000); Bodamer & Gardner (2002) Washoe (& others) American Sign Language (ASL) Semi Home rearing, no vocalization, imitation and sign moulding, reward.
Terrace et al (1979) Nim Chimsky ASL 'Home rearing', many trainers, imitation.
Muncer & Etlinger (1981) Jane ASL (limited vocabulary of objects, prepositions and conjunctions. 1 year of lab style reward training, then 'Critical trials' in novel tests.
Premack (1970-1986) Sarah (& others) Plastic tokens as symbols for objects, verbs, and abstract categories. Lab style sessions, examples and initial reward. Attempts to control for experimenter effects.
Savage-Rumbaugh et al (1973-1985) Austin and Sherman 'Lexigrams' (Arbitrary visual symbols on a keyboard and computer-controlled display. Examples, and initially specific reward training, (later more general encouragement)
Savage-Rumbaugh et al (1986 and later years) Greenfield and Savage-Rumbaugh (1990, 1993) Kanzi (& Mulika) Lexigrams on portable keyboard & ASL & spoken English Initially imitation of natural mother: very rich environment but no formal training and no food reward; learning during ‘informal’ daily activities.

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Main Sources — Primate Cognition

Roberts, W.A (1998) Principles of Animal Cognition. Boston: McGraw-Hill. Chapter 12 "Primate Cognition".(1 copy on short loan at BK; 4 loan copies)

Walker, S.F. (1985). Animal Thought. Routledge & Kegan Paul: London pp 339-388

Walker, S.F. (1987b). Animal Learning. Routledge & Kegan Paul: London. pp. 332-357.

Further Reading — Primate Cognition

Boysen, ST and Himes, GT (1999) Current issues and emerging theories in animal cognition. Annual Review of Psychology, Vol.50, Pp.683-705.

www. version of this paper (If at BK or using BK dial-up software)

Heyes, C.M. (1998) Theory of mind in nonhuman primates. Behavioural and Brain Sciences, 21, 108-148.

www.pdf version of this paper(v.long (If at BK or using BK dial-up software) Preprint of just the paper

Macphail, EM (1996) Cognitive function in mammals - the evolutionary perspective . Cognitive Brain Research, Vol.3, No.3-4, Pp.279-290.

Pearce J.M. (1997) Animal Learning and Cognition 2nd Edition. Hove: Psychology Press. 156.315 PEA in new section at Birkbeck. 1 normal and 1 Short Loan copy (pages 1-14, 237- 251, 253-287)

Tomasello, M. (2000). Primate cognition: Introduction to the issue. Cognitive Science, 24(3), 351-361.

Walker, S.F. (1987a). The evolution and dissolution of language. In Ellis, A. (ed.), Progress in the Psychology of Language. Volume 3. Lawrence Erlbaum: London. pp 28-41 only (Short Loan).  


More Additional References (Not normally for further reading)

Adachi, I., Kuwahata, H., & Fujita, K. (2007). Dogs recall their owner's face upon hearing the owner's voice. Animal Cognition, 10(1), 17-21.

Baron-Cohen, S (1992) How monkeys do things with "words". Behavioural and Brain Sciences, 15, 148-9.

Barton, RA (1998) Visual specialization and brain evolution in primates. Proceedings of the Royal Society of London Series B-Biological Sciences, Vol.265, No.1409, Pp.1933-1937.

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.

Boesch, C. (2002). Cooperative hunting roles among Tai chimpanzees. Human Nature-an Interdisciplinary Biosocial Perspective, 13(1), 27-46.

Brauer, J., Call, J., & Tomasello, M. (2005). All great ape species follow gaze to distant locations and around barriers. Journal of Comparative Psychology, 119(2), 145-154.

Bush, E. C., & Allman, J. M. (2004). The scaling of frontal cortex in primates and carnivores. Proceedings of the National Academy of Sciences of the United States of America, 101(11), 3962-3966.

Buxhoeveden, D. P., Switala, A. E., Roy, E., Litaker, M., & Casanova, M. F. (2001). Morphological differences between minicolumns in human and nonhuman primate cortex. Amer. J. of Physical Anthropology, 115(4), 361-371.

Call, J. (2001). Chimpanzee social cognition. Trends in Cognitive Sciences, 5(9), 388-393.

Call, J., Carpenter, M., & Tomasello, M. (2005). Copying results and copying actions in the process of social learning: chimpanzees (Pan troglodytes) and human children (Homo sapiens). Animal Cognition, 8(3), 151-163.

Cantalupo, C., & Hopkins, W. D. (2001). Asymmetric Broca's area in great apes - A region of the ape brain is uncannily similar to one linked with speech in humans. Nature, 414(6863), 505-505.

Collier-Baker, E., Davis, J. M., Nielsen, M., & Suddendorf, T. (2006). Do chimpanzees (Pan troglodytes) understand single invisible displacement? Animal Cognition, 9(1), 55-61.

Crockford, C., Herbinger, I., Vigilant, L., & Boesch, C. (2004). Wild chimpanzees produce group-specific calls: a case for vocal learning? Ethology, 110(3), 221-243.

Diamond, J. (1992) The Rise and Fall of the Third Chimpanzee. London:Vintage.

Elman, J. L. (2005). Connectionist models of cognitive development: where next? Trends in Cognitive Sciences, 9(3), 111-117.

Enard, W., Khaitovich, P., Klose, J., Zollner, S., Heissig, F., Giavalisco, P., Nieselt-Struwe, K., Muchmore, E., Varki, A., Ravid, R., Doxiadis, G. M., Bontrop, R. E., & Paabo, S. (2002). Intra- and interspecific variation in primate gene expression patterns. Science, 296(5566), 340-343.

Enard, W., Przeworski, M., Fisher, S. E., Lai, C. S. L., Wiebe, V., Kitano, T., Monaco, A. P., & Paabo, S. (2002). Molecular evolution of FOXP2, a gene involved in speech and language. Nature, 418(6900), 869-872.

Evans, P. D., Vallender, E. J., & Lahn, B. T. (2006). Molecular evolution of the brain size regulator genes CDK5RAP2 and CENPJ. Gene, 375, 75-79.

Gallup, G.G., Jr. (1970) Chimpanzees: self-recognition. Science, 167, 86-7.

Gardner, B.T. and Gardner, R.A. (1971) Two-way communication with an infant chimpanzee. In Schrier, A.M. & Stollnitz, F. (eds.) Behaviour of Nonhuman Primates. Vol. 4. Academic Press: New York, 117-83.

Gardner, B.T. and Gardner, R.A. (1985) Signs of intelligence in cross-fostered chimpanzees. Philosophical Transactions of the Royal Society, B, 308, 159-176.

Gardner, R.A. and Gardner, B.T. (1969) Teaching sign language to a chimpanzee. Science, 165, 664-72.

Giurfa, M., Zhang,S., Jenett,A., Menzel,R. & Srinivasan, M.V. (2001) The concepts of 'sameness' and 'difference' in an insect Nature 410, 930 - 933

Greenfield, P.M. and Savage-Rumbaugh, E.S. (1990) Grammatical combination in Pan paniscus: Processes of learning and invention in the evolution and development of language. In S.T. Parker and K.R. Gibson (eds) "Language" and Intelligence in Monkeys and Apes: Comparative Developmental Perspectives. Cambridge University Press, 540-578.

Greenfield, P.M. and Savage-Rumbaugh, E.S. (1993) Comparing communicative competence in child and chimp: the pragmatics of repetition. Journal of Child Language, 20, 1-26.

Hauser, M. D., Chomsky, N., & Fitch, W. T. (2002). The faculty of language: What is it, who has it, and how did it evolve? Science, 298(5598), 1569-1579.

Hayes, K.J. and Hayes, C. (1953) Picture perception in a home-raised chimpanzee. Journal of Comparative and Physiological Psychology, 46, 470-4.

Hayes, K.J. and Nissen, C.H. (1971) Higher mental functions of a home raised chimpanzee. In Schrier, A.M. and Stollnitz, F. (eds.) Behaviour of Nonhuman Primates, Vol 4. Academic Press: New York, 59-115.

Hopkins, W. D., Taglialatela, J. P., & Leavens, D. A. (2007). Chimpanzees differentially produce novel vocalizations to capture the attention of a human. Animal Behaviour, 73, 281-286.

Humphrey, N.K. (1976) The social function of intellect. In P.P.G. Bateson and R.A. Hinde (eds) Growing Points in Ethology. Cambridge University Press, 303-21.

Jacobs, G. H., Williams, G. A., Cahill, H., & Nathans, J. (2007). Emergence of novel color vision in mice engineered to express a human cone photopigment. Science, 315(5819), 1723-1725.

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.

Jerison, H.J. (1973) Evolution of the Brain and Intelligence. Academic Press: London.

Jolly, A. (1966) Lemur social behaviour and primate intelligence. Science, 153, 501-506

Kaminski, J., Call, J., & Fischer, J. (2004). Word learning in a domestic dog: Evidence for "fast mapping". Science, 304(5677), 1682-1683.

Kaminski, J., Riedel, J., Call, J., & Tomasello, M. (2005). Domestic goats, Capra hircus, follow gaze direction and use social cues in an object choice task. Animal Behaviour, 69, 11-18.

Kellogg, W.A. and Kellogg, L.A. (1933) The Ape and the Child. New York: McGraw-Hill (67 IAV Kel, Senate House)

Kuraoka, K., & Nakamura, K. (2007). Responses of single neurons in monkey amygdala to facial and vocal emotions. Journal of Neurophysiology, 97(2), 1379-1387

Leslie, A.M. (1987) Pretence and representation: The origins of "theory of mind". Psychological Review, 94, 412-26.

Maclarnon, A., & Hewitt, G. (2004). Increased breathing control: Another factor in the evolution of human language. Evolutionary Anthropology, 13(5), 181-197.

Macphail, E. M., & Bolhuis, J. J. (2001). The evolution of intelligence: adaptive specializations versus general process. Biological Reviews, 76(3), 341-364.

Macphail, E.M. (1985). Vertebrate intelligence: the null hypothesis. Philosophical Transactions of the Royal Society, B, 308, 37-51.

Macphail, E.M. (1987) The comparative psychology of intelligence. Behavioural and Brain Sciences, 10, 645-695.

Macphail, E.M. (1998) The Evolution of Consciousness. Oxford: Oxford University Press.

Marino, L (1998) A comparison of encephalization between odontocete cetaceans and anthropoid primates. Brain Behavior and Evolution, Vol.51, No.4, Pp.230-238.

Matsuzawa, T. (2007). Comparative cognitive development. Developmental Science, 10(1), 97-103.

Melis, A. P., Hare, B., & Tomasello, M. (2006). Chimpanzees recruit the best collaborators. Science, 311(5765), 1297-1300.

Miller, E. K., Freedman, D. J., & Wallis, J. D. (2002). The prefrontal cortex: categories, concepts and cognition. Philosophical Transactions of the Royal Society of London Series B-Biological Sciences, 357(1424), 1123-1136.

Pack, A. A., & Herman, L. M. (2007). The dolphin's (Tursiops truncatus) understanding of human gazing and pointing: Knowing what and where. Journal of Comparative Psychology, 121(1), 34-45.

Pepperberg, I. M., & Shive, H. R. (2001). Simultaneous development of vocal and physical object combinations by a grey parrot (Psittacus erithacus): Bottle caps, lids, and labels. Journal of Comparative Psychology, 115(4), 376-384.

Pika, S., & Mitani, J. (2006). Referential gestural communication in wild chimpanzees (Pan troglodytes). Current Biology, 16(6), R191-R192.

Pinker, S., & Jackendoff, R. (2005). The faculty of language: what's special about it? Cognition, 95(2), 201-236.

Pollard, K. S., Salama, S. R., Lambert, N., Lambot, M. A., Coppens, S., Pedersen, J. S., et al. (2006). An RNA gene expressed during cortical development evolved rapidly in humans. Nature, 443(7108), 167-172.

Ponting, C., & Jackson, A. P. (2005). Evolution of primary microcephaly genes and the enlargement of primate brains. Current Opinion in Genetics & Development, 15(3), 241-248.

Povinelli, D. J., & Vonk, J. (2004). We don't need a microscope to explore the chimpanzee's mind. Mind & Language, 19(1), 1-28.

Povinelli, D. J., Bering, J. M., & Giambrone, S. (2000). Toward a science of other minds: Escaping the argument by analogy. Cognitive Science, 24(3), 509-541.

Premack, D. (1970) A functional analysis of language. Journal of the Experimental Analysis of Behaviour, 14, 107-25.

Premack, D. (1971) Language in chimpanzee. Science, 172, 808-22.

Premack, D. (1976) Intelligence in Ape and Man. Lawrence Erlbaum Associates: Hillsdale, N.J.

Premack, D. (1986) Gavagai! or the Future History of the Animal Language Controversy. MIT Press: London.

Premack, D. and Woodruff, G. (1978) Chimpanzee problem solving: a test for comprehension. Science, 202, 532-5.

Preuss, T. M., Caceres, M., Oldham, M. C., & Geschwind, D. H. (2004). Human brain evolution: Insights from microarrays. Nature Reviews Genetics, 5(11), 850-860.

Reader, S. M., & Laland, K. N. (2002). Social intelligence, innovation, and enhanced brain size in primates. Proceedings of the National Academy of Sciences of the United States of America, 99(7), 4436-4441.

Regan, B. C., Julliot, C., Simmen, B., Vienot, F., Charles-Dominique, P., & Mollon, J. D. (2001). Fruits, foliage and the evolution of primate colour vision. Philosophical Transactions of the Royal Society of London Series B-Biological Sciences, 356(1407), 229-283.

Rilling, J. K., & Seligman, R. A. (2002). A quantitative morphometric comparative analysis of the primate temporal lobe. Journal of Human Evolution, 42(5), 505-533.

Rivas, E. (2005). Recent use of signs by chimpanzees (Pan troglodytes) in interactions with humans. Journal of Comparative Psychology, 119(4), 404-417.

Rizzolatti, G and Arbib, M.A (1998). Language within our grasp. Trends in Neurosciences, 21, 188-194

Rumbaugh, D. and von Glaserfeld, E. (1973) Reading and sentence completion by a chimpanzee. Science, 182, 731-3.

Savage-Rumbaugh, E.S., Murphy, J.,Sevik, R.A., Brakkem K.E., Williams, S.L. and Rumbaugh, D.M (1993) Language comprehension in ape and child. Monographs of the Society for Research in Child Development, 58, (nos 3-4) 1-252.

Savage-Rumbaugh, E.S., Rumbaugh, D.M. and Boysen, S. (1978) Linguisticaly mediated tool use and exchange by chimpanzees (Pan troglodytes) Behavioural and Brain Sciences, 1, 539-54.

Savage-Rumbaugh, E.S., Rumbaugh, D.M., Smith, S.T. and Lawson, J. (1980) Reference: the linguistic essential. Science, 210, 922-5.

Savage-Rumbaugh, E.S., Sevik, R.A., Rumbaugh, D.M. and Rubert, E. (1985) The capacity of animals to acquire language: do species differences have anything to say to us. Philosophical Transactions of the Royal Society, B, 308, 177-85.

Savage-Rumbaugh, E.S., Shanker, S.G. and Talbot J.T. (1998) Apes, Language, and the Human Mind. New York : Oxford University Press

Schenker, N. M., Desgouttes, A. M., & Semendeferi, K. (2005). Neural connectivity and cortical substrates of cognition in hominoids. Journal of Human Evolution, 49(5), 547-569.

Semendeferi, K., Lu, A., Schenker, N., & Damasio, H. (2002). Humans and great apes share a large frontal cortex. Nature Neuroscience, 5(3), 272-276.

Sherwood, C. C., Stimpson, C. D., Raghanti, M. A., Wildmand, D. E., Uddin, M., Grossman, L. I., et al. (2006). Evolution of increased glia-neuron ratios in the human frontal cortex. Proceedings of the National Academy of Sciences of the United States of America, 103(37), 13606-13611.

Shyan, M.R. and Herman, L.M. (1987) Determinants of recognition of gestural signs in an artificial language by Atlantic bottlenosed dolphins (Tursiops truncatus) and humans (Homo sapiens) Journal of Comparative Psychology, 101, 112-125.

Skinner, B.F. (1957) Verbal Behaviour. Appleton Century Crofts: New York

Slotnick, B. (2001) Animal cognition and the rat olfactory system Trends in Cognitive Sciences, 5, no 5, 216-222.

Soproni, K., Miklosi, A., Topal, J., & Csanyi, V. (2002). Dogs' (Canis familiaris) responsiveness to human pointing gestures. Journal of Comparative Psychology, 116(1), 27-34.

Suda, C., & Call, J. (2005). Piagetian conservation of discrete quantities in bonobos (Pan paniscus), chimpanzees (Pan troglodytes), and orangutans (Pongo pygmaeus). Animal Cognition, 8(4), 220-235.

Suddendorf, T., & Whiten, A. (2001). Mental evolution and development: Evidence for secondary representation in children, great apes, and other animals. Psychological Bulletin, 127(5), 629-650.

Tang, B. L. (2006). Molecular genetic determinants of human brain size. Biochemical and Biophysical Research Communications, 345(3), 911-916.

Terrace, H.S. (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 Chimpanzee Sequencing and Analysis Consortium. (2005). Initial sequence of the chimpanzee genome and comparison with the human genome. 437(7055), 69-87.

Thompson, R. K. R., & Oden, D. L. (2000). Categorical perception and conceptual judgments by nonhuman primates: The paleological monkey and the analogical ape. Cognitive Science, 24(3), 363-396.

Tomasello, M. (2001). Cultural transmission - A view from chimpanzees and human infants. Journal of Cross-Cultural Psychology, 32(2), 135-146.

Tomasello, M. and Call, J. (1997) Primate Cognition. Oxford: Oxford University Press. (599.81513 TOM -1 wk loan)

Tomasello, M., & Rakoczy, H. (2003). What makes human cognition unique? From individual to shared to collective intentionality. Mind & Language, 18(2), 121-147.

Tomasello, M., Call, J., & Hare, B. (2003). Chimpanzees understand psychological states - the question is which ones and to what extent. Trends in Cognitive Sciences, 7(4), 153-156.

Tomasello, M., Carpenter, M., Call, J., Behne, T., & Moll, H. (2005). Understanding and sharing intentions: The origins of cultural cognition. Behavioral and Brain Sciences, 28(5), 675-+.

Tsao, D. Y., Freiwald, W. A., Tootell, R. B. H., & Livingstone, M. S. (2006). A cortical region consisting entirely of face-selective cells. Science, 311(5761), 670-674.

Ungerleider, LG, Courtney, SM & Haxby, JV (1998) A neural system for human visual working memory. Proceedings of the National Academy of Sciences of the United States of America, Vol.95, No.3, Pp.883-890.

Walker, R., Hill, K., Burger, O., & Hurtado, A. M. (2006). Life in the slow lane revisited: Ontogenetic separation between chimpanzees and humans. American Journal of Physical Anthropology, 129(4), 577-583.

Whiten, A., & Byrne Richard, W. (1997). Machiavellian Intelligence II : Extensions and Evaluations. Cambridge: Cambridge University Press. (Senate House 67 IQD Mac)

Wich, S. A., & de Vries, H. (2006). Male monkeys remember which group members have given alarm calls. Proceedings of the Royal Society B-Biological Sciences, 273(1587), 735-740.

Wrangham, R. W., Wilson, M. L., & Muller, M. N. (2006). Comparative rates of violence in chimpanzees and humans. Primates, 47(1), 14-26.

Yip, M. J. (2006). The search for phonology in other species. Trends in Cognitive Sciences, 10(10), 442-446.

Zuberbuhler, K. (2006). Language evolution: The origin of meaning in primates. Current Biology, 16(4), R123-R125