Metacognition in Animals 1Metacognition in animalsJonathon D. Crystal & Allison L. FooteUniversity of GeorgiaMetacognition is thinking about thinking. There is considerable interest in developing animal models of metacognition to provide insight about the evolution of mind and a basis for investigating neurobiological mechanisms of cognitive impair-ments in people. Formal modeling of low-level (i.e., alternative) mechanisms has recently demonstrated that prevailing standards for documenting metacognition are inadequate. Indeed, low-level mechanisms are sufficient to explain data from existing methods. Consequently, an assessment of what is ‘lost’ (in terms of existing methods and data) necessitates the development of new, innovative methods for metacognition. Development of new methods may prompt the establishment of new standards for documenting metacognition. Keywords: Metacognition, comparative metacognition, uncertainty monitoring, metamemory, quantitative modeling. A defining feature of human existence is the ability to re-flect on one’s own mental processes, termed metacognition (Descartes, 1637; Metcalfe & Kober, 2005). Consequently, a fundamental question in comparative cognition is whether nonhuman animals (henceforth animals) have knowledge of their own cognitive states (Smith, Shields, & Washburn, 2003). Answering this question not only provides critical information about the evolution of mind (Emery & Clayton, 2001), but also provides a potential framework for investi-gating the neurobiological basis of cognitive impairments in people (Hoerold et al., 2008; Robinson, Hertzog, & Dun-losky, 2006; Shimamura & Metcalfe, 1994). The presentation of a stimulus gives rise to an internal rep-resentation of that stimulus (which is referred to as the pri-mary representation). Primary representations are the basis for many behaviors. For example, when presented with an item on a memory test, it is possible to evaluate familiar-ity with the item to render a judgment that the item is new or old. Metacognition involves a secondary representation which operates on a primary representation. For example, a person might know that he does not know the answer to a question, in which case appropriate actions might be taken (such as deferring until additional information is available). To document metacognition, we need a method that assigns performance to the secondary representation (i.e., we need to be certain that performance is not based on the primary representation). Carruthers (2008) distinguishes between first-order ex-planations and metacognition. First-order explanations are “world-directed” rather than “self-directed” according to Carruthers. According to this view, first-order explanations are representations about stimuli in the world (i.e., beliefs about the world), whereas metacognition involves represen-tations about beliefs (i.e., knowing that you hold a particu-lar belief). Note that according to the definition provided above, metacognition involves knowledge about one’s cog-nitive state. Thus, a variety of other conditional arrange-ments would not constitute metacognition. For example, discriminating an internal, physiological state would not constitute metacognition. Similarly, discriminating hierar-chical relations between a variety of stimuli and responses (e.g., occasion setting) would not constitute metacognition. Carruthers argues that putative metacognitive phenomena in animals may be explained in first-order terms1. With human participants, we can ask people to report about their subjective experiences using language. Self Jonathon D. Crystal and Allison L. Foote, Department of Psy-chology, University of Georgia, Athens GA 30602-3013 This work was supported by National Institute of Mental Health grant R01MH080052 to JDC. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute of Mental Health or the National Institutes of Health. Correspondence concerning this article should be addressed to JDC at [email protected] 4, pp 1 -162009ISSN: 1911-4745 doi: 10.3819/ccbr.2009.40001 © Jonathon D. Crystal 2009Metacognition in Animals 2reports of subjective experiences play a prominent role in investigations of metacognition in people (Nelson, 1996). Although these reports may not be perfect, they provide a source of information that is not available from nonverbal animals. Consequently, the difficult problem of assessing metacognition in animals requires the development of be-havioral techniques from which we may infer the existence of metacognition. A frequent approach is to investigate the possibility that an animal knows when it does not know the answer to a question; in such a situation, an animal with metacognition would be expected to decline to take a test, particularly if some alternative, desirable outcome is avail-able. Importantly, it is necessary to rule out simpler, alterna-tive explanations. In particular, we need to determine that the putative case of metacognition is based on a secondary representation rather than on a primary representation. For example, if principles of associative learning or habit for-mation operating on a primary representation may account for putative metacognition data, then it would be inappropri-ate to explain such data based on metacognition (i.e., based on a secondary representation); the burden of proof favors primary representations, by application of Morgan’s canon (Morgan, 1906). We shall refer to explanations that apply primary representations without appeal to secondary rep-resentations as simpler or low-level alternative hypotheses to metacognition. Such considerations raise the question of the standards by which putative metacognition data are to be judged. A standard specifies criteria that must be met to infer metacognition using methods that cannot be explained by simpler, alternative hypotheses. We recognize that the details of an alternative hypothesis need to be specific (and specification is provided below), but it is worth recognizing that alternatives to metacognition are simpler (i.e., only pri-mary representations are required). We also note that use of a