Since the BBS article in which Premack and Woodruff (1978) asked “Does the chimpanzee have a theory of mind?,” it has been repeatedly claimed that there is observational and experimental evidence that apes have mental state concepts, such as “want” and “know.” Unlike research on the development of theory of mind in childhood, however, no substantial progress has been made through this work with nonhuman primates. A survey of empirical studies of imitation, self-recognition, social relationships, deception, role-taking, and perspective-taking suggests (...) that in every case where nonhuman primate behavior has been interpreted as a sign of theory of mind, it could instead have occurred by chance or as a product of nonmentalistic processes such as associative learning or inferences based on nonmental categories. Arguments to the effect that, in spite of this, the theory of mind hypothesis should be accepted because it is more parsimonious than alternatives or because it is supported by convergent evidence are not compelling. Such arguments are based on unsupportable assumptions about the role of parsimony in science and either ignore the requirement that convergent evidence proceed from independent assumptions, or fail to show that it supports the theory of mind hypothesis over nonmentalist alternatives. Progress in research on theory of mind requires experimental procedures that can distinguish the theory of mind hypothesis from nonmentalist alternatives. A procedure that may have this potential is proposed. It uses conditional discrimination training and transfer tests to determine whether chimpanzees have the concept “see.” Commentators are invited to identify flaws in the procedure and to suggest alternatives. Key Words: apes; associative learning; concepts; convergence; deception; evolution of intelligence; folk psychology; imitation; mental state attribution; monkeys; parsimony; perspective-taking; primates; role-taking; self-recognition; social cognition; social intelligence; theory of mind. (shrink)

The commentators do not contest the target article's claim that there is no compelling evidence of theory of mind in primates, and recent empirical studies further support this view. If primates lack theory of mind, they may still have other behavior control mechanisms that are adaptive in complex social environments. The Somatic Marker Mechanism (SMM) is a candidate, but the SMM hypothesis postulates a much weaker effect of natural selection on social cognition than the theory of mind hypothesis (on inputs (...) to cognitive mechanisms, not on the mechanisms themselves), and there is currently no evidence that it is specific to social stimuli or to primates. “Two Guesser” training would make the goggles test too chauvinistic, and in its current form the goggles problem could not be solved by physical matching because, while wearing goggles, an individual cannot see itself seeing. (shrink)

The target article argued that there is currently no reliable evidence of theory of mind in nonhuman primates and proposed research methods for future use in this field. Some commentators judged the research proposals to be too chauvinist (in danger of falsely denying that primates attribute mental states), but a majority judged them to be too liberal (in danger of falsely affirming theory of mind in primates). The most valuable comments from both camps exemplified “experimental thought,” the obverse of “thought (...) experiments,” and recommended specific alterations and alternatives to the studies I proposed. This Response evaluates these recommendations and presents a revised version of the proposals that appear in the target article. Other valuable commentary cast doubt on the assumption that people have a theory of mind, aired the possibility that language may be a prerequisite for either possession or detection of a theory of mind, questioned the notion of critical experiments, and emphasized the distinction between attribution of sight and belief. In addition to commenting on these issues, I respond to objections to my interpretation of existing research on self-recognition, imitation, and deception. (shrink)

Immediate imitation is likely to be a major, direct input to Barresi & Moore's level 2 competence, but deferred imitation is unlikely to play a key role in the transition to level 3, because the attribution of first person knowledge is neither a necessary cause nor an obvious consequence of deferred imitation, and deferred imitation does not correlate phylogenetically with capacities that more plausibly either yield or reflect a concept of intentional agency.