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ScienceWeek
COGNITIVE SCIENCE: ON ANIMAL COGNITION
The following points are made by James L. Gould (Current Biology 2004 14:R372):
1) When Rene Descartes (1596-1650) suggested that nonhuman animals are machines, he made formal a view widely taken for granted by most thinkers in the Western tradition. In the process, he conveniently supplied a rationale for the curious assumption that only humans have souls. (Swimming against the tide, Saint Jerome argued in the early 400s that certain animals might have small souls.)
2) In the 19th century, Darwin's theory of evolution by natural selection licensed a new take on the problem: the difference between human and animal mentality was more likely to be one of degree. His enthusiastic followers began to discover that other species are very clever indeed. G.J. Romanes (1848-1894), in his Animal Intelligence (1882) found thought in virtually every creature from insects to mammals, but was especially impressed with primates.
3) By 1900, the number of smart-animal stories reached flood stage. Theodore Roosevelt and the well-known writer John Burroughs took on what they called the Nature Fakers, who fudged the truth between fiction and fact. They mounted a blistering attack, for instance, on William Long's story of a woodcock that set its own broken leg using a cast made of mud. During the height of the debate came a gentle German schoolmaster and his famous pupil, Clever Hans. Hans, a Russian trotting horse, had learned the rudiments of addition and subtraction. He was known to read and spell, compute fractions and tell time, understand music and calculate dates. He tapped out most of his answers, but could also respond by pointing his nose.
4) Many notable experts observed Hans and questioned him with remarkable success, even in von Osten's absence. A panel formally appointed to investigate concluded that no trickery could be involved, but the members were quite reasonably worried that Hans was rather too clever. They engaged the psychologist Oskar Pfungst to study the horse further. Using a double-blind technique, Pfungst discovered that Hans was "reading" the tension in his audience: when he reached the correct number of taps, the observers unwittingly relaxed.
5) Perhaps the most even-handed thing that can be said about studies of animal cognition is that they have made animals look smarter and humans dumber than either group formerly appeared. Individual opinion differs on where to draw the line on thinking, but it seems clear that much of what we once took to be cognitive and largely human now appears to be widespread and at least partially innate. The power of automatic learning (in humans as well as animals) is much greater than we had thought, while evolution seems to have smoothed the path to abilities once considered intellectually impressive.(1-5)
References:
1. De Waal, F. (1982). Chimpanzee Politics. (London: Jonathan Cape), Gould, J.L. (1982). Ethology. (New York: Norton)
2. Gould, J.L. and Gould, C.G. (1999). The Animal Mind. (New York: W.H. Freeman)
3. Gould, J.G. and Marler, P. (1987). Learning by instinct. Sci. Am. 256, (1) 74-85
4. Griffin, D.R. (2001). Animal Minds: Beyond Cognition to Consciousness. (Chicago: University of Chicago)
5. In Animal Cognition in Nature. (1998). Pepperberg, I., Balda, R., and Kamil, E.C. eds. (San Diego: Academic Press)
Current Biology http://www.current-biology.com
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COGNITIVE SCIENCE: ON WORD-LEARNING IN DOGS
The following points are made by J. Kaminski et al (Science 2004 304:1682):
1) The rate at which most toddlers acquire their vocabulary is astounding: From about 2 years of age, typical English-speaking children incorporate about 10 new words per day into their vocabulary until they reach an average vocabulary size of 60,000 words by the time they graduate from high school (1). Several studies have shown that children have a set of operating principles that guide the task of word learning (2-4). However, it remains a matter of debate which of these principles are unique to language learning and which are more general cognitive abilities that may be shared with other living creatures.
2) The authors investigated the outer limits of a domestic dog's "word learning"; that is, his ability to acquire the relation between a word and the object that this word refers to (the referent). By studying his retrieval behavior with familiar and novel items, the authors specifically tested whether he would be able to infer the referent of a new word by exclusion learning: that is, to "fast map" (5) and retain this knowledge over time.
3) The study animal, Rico, is a border collie and was born in December 1994. He lives as a pet with his owners and was reported by them to know the labels of over 200 items, mostly children's toys and balls, which he correctly retrieved upon request. Rico was first introduced to fetching items when he was 10 months of age, when his owners placed three different items in different locations around the flat and asked the dog for one of these items. Rico was rewarded with food or play if he fetched the correct object. He was gradually familiarized with an increasing number of items. Typically, the owners introduced new items by presenting them and saying their name two or three times. Rico then got the chance to play with the new item, and it was subsequently integrated into the collection of other items.
4) The first experiment was designed to assess Rico's ability to correctly retrieve his various items under controlled conditions. The authors randomly assigned the 200 items he was reportedly familiar with to 20 sets of 10 different items each. While the owner waited with the dog in a separate room, the experimenter arranged a set of items in the experimental room and then joined the owner and the dog. Next, the experimenter instructed the owner to request the dog to bring two randomly chosen items (one after the other) from the adjacent room. While Rico searched for the requested item, he could not see the owner or the experimenter. He retrieved a total of 37 out of 40 items correctly. This first experiment demonstrated that Rico indeed knew the labels of these items.
5) In summary: During speech acquisition, children form quick and rough hypotheses about the meaning of a new word after only a single exposure -- a process dubbed "fast mapping". The authors provide evidence that a border collie, Rico, is able to fast map. Rico knew the labels of over 200 different items. He inferred the names of novel items by exclusion learning and correctly retrieved those items immediately as well as 4 weeks after the initial exposure. The authors suggest that fast mapping thus appears to be mediated by general learning and memory mechanisms also found in other animals and not by a language acquisition device that is special to humans.
References (abridged):
1. P. Bloom, How Children Learn the Meanings of Words (MIT Press, Cambridge, MA, 2000)
2. D. A. Baldwin, Dev. Psychol. 29, 832 (1993)
3. C. B. Mervis, J. Bertrand, Child Dev. 65, 1662 (1994)
4. M. Tomasello, Constructing a Language (Harvard Univ. Press, Cambridge, MA, 2003)
5. L. Markson, P. Bloom, Nature 385, 813 (1997)
Science http://www.sciencemag.org
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ANIMAL BEHAVIOR: ON ANTHROPOMORPHISM
The following points are made by Clive D. Wynne (Nature 2004 428:606):
1) The complexity of animal behavior naturally prompts us to use terms that are familiar from everyday descriptions of our own actions. Charles Darwin (1809-1882) used mentalistic terms freely when describing, for example, pleasure and disappointment in dogs; the cunning of a cobra; and sympathy in crows. Darwin's careful anthropomorphism, when combined with meticulous description, provided a scientific basis for obvious resemblances between the behavior and psychology of humans and other animals. It raised few objections.
2) The 1890s saw a strong reaction against ascribing conscious thoughts to animals. In the UK, the canon of Conwy Lloyd Morgan (1852-1936) forbade the explanation of animal behavior with "a higher psychical faculty" than demanded by the data. In the US, Edward Thorndike (1874-1949) advocated replacing the use of anecdotes in the study of animal behavior with controlled experiments. He argued that when studied in controlled and reproducible environments, animal behavior revealed simple mechanical laws that made mentalistic explanations unnecessary.
3) This rejection of anthropomorphism was one of the few founding principles of behaviorism that survived the rise of ethological and cognitive approaches to studying animal behavior. But after a century of silence, recent decades have seen a resurgence of anthropomorphism. This movement was led by ethologist Donald Griffin, famous for his discovery of bat sonar. Griffin argued that the complexity of animal behavior implies conscious beliefs and desires, and that an anthropomorphic explanation can be more parsimonious than one built solely on behavioral laws. Griffin postulated, "Insofar as animals have conscious experiences, this is a significant fact about their nature and their lives." Animal communication particularly impressed Griffin as implying animal consciousness.
4) Griffin has inspired several researchers to develop ways of making anthropomorphism into a constructive tool for understanding animal behavior. Gordon Burghardt was keen to distinguish the impulse that prompts children to engage in conversations with the family dog (naive anthropomorphism) from "critical anthropomorphism", which uses the assumption of animal consciousness as a "heuristic method to formulate research agendas that result in publicly verifiable data that move our understanding of behavior forward." Burghardt points to the death-feigning behavior of snakes and possums as examples of complex and apparently deceitful behaviors that can best be understood by assuming that animals have conscious states.
5) But anthropomorphism is not a well-developed scientific system. On the contrary, its hypotheses are generally nothing more than informal folk psychology, and may be of no more use to the scientific psychologist than folk physics to a trained physicist. Although anthropomorphism may on occasion be a source of useful hypotheses about animal behavior, acknowledging this does not concede the general utility of an anthropomorphic approach to animal behavior.(1-4)
References:
1. Blumberg, M. S. & Wasserman, E. A. Am. Psychol. 50, 133-144 (1995)
2. De Waal, F. B. M. Phil. Top. 27, 255-280 (1999)
3. Mitchell, R. W. et al. Anthropomorphism, Anecdotes and Animals (State Univ. New York Press, New York, 1997)
4. Wynne, C. D. L. Do Animals Think? (Princeton Univ. Press, Princeton, New Jersey, 2004)
Nature http://www.nature.com/nature
ScienceWeek http://scienceweek.com
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