Behavioral and Brain Sciences

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Darwin's mistake: Explaining the discontinuity between human and nonhuman minds

Derek C. Penna1, Keith J. Holyoaka2 and Daniel J. Povinellia3

a1 Department of Psychology, University of California–Los Angeles, Los Angeles, CA 90095; Cognitive Evolution Group, University of Louisiana, Lafayette, LA 70504 dcpenn@ucla.edu http://reasoninglab.psych.ucla.edu/ http://www.cognitiveevolutiongroup.org/

a2 Department of Psychology, University of California–Los Angeles, Los Angeles, CA 90095 holyoak@lifesci.ucla.edu http://reasoninglab.psych.ucla.edu/

a3 Cognitive Evolution Group, University of Louisiana, Lafayette, LA 70504 ceg@louisiana.edu http://www.cognitiveevolutiongroup.org/

Abstract

Over the last quarter century, the dominant tendency in comparative cognitive psychology has been to emphasize the similarities between human and nonhuman minds and to downplay the differences as “one of degree and not of kind” (Darwin 1871). In the present target article, we argue that Darwin was mistaken: the profound biological continuity between human and nonhuman animals masks an equally profound discontinuity between human and nonhuman minds. To wit, there is a significant discontinuity in the degree to which human and nonhuman animals are able to approximate the higher-order, systematic, relational capabilities of a physical symbol system (PSS) (Newell 1980). We show that this symbolic-relational discontinuity pervades nearly every domain of cognition and runs much deeper than even the spectacular scaffolding provided by language or culture alone can explain. We propose a representational-level specification as to where human and nonhuman animals' abilities to approximate a PSS are similar and where they differ. We conclude by suggesting that recent symbolic-connectionist models of cognition shed new light on the mechanisms that underlie the gap between human and nonhuman minds.

Derek C. Penn received a Masters Degree from Boston University in Philosophy and Literary Semiotics in 1987. He spent the next 15 years on the trading floors of various Wall Street investment firms and in Silicon Valley as a software entrepreneur. In 2002 he retired from the business world to pursue his life-long interest in comparative psychology. He is currently affiliated with the Cognitive Evolution Group, University of Louisiana, and the University of California, Los Angeles and is working on a trade book with Daniel J. Povinelli based on the hypotheses proposed in the present article.

Keith J. Holyoak is a Distinguished Professor of Psychology at the University of California, Los Angeles. The author of more than 180 research articles, his books include Mental Leaps: Analogy in Creative Thought (co-authored with Paul Thagard, MIT Press, 1995) and The Cambridge Handbook of Thinking and Reasoning (co-edited with Robert Morrison, Cambridge University Press, 2005). A past recipient of a Guggenheim Fellowship, Holyoak is a Fellow of the American Association for the Advancement of Science, the Association for Psychological Science, the Cognitive Science Society, and the Society for Experimental Psychology.

Daniel J. Povinelli is a Professor of Biology at the University of Louisiana. He is the recipient of an American Psychological Association Award for an Early Career Contribution to Psychology, an National Science Foundation Young Investigator Award, and a Centennial Fellowship from the James S. McDonnell Foundation. He is a Fellow of the Association for Psychological Science and was named one of “20 Scientists to Watch in the Next 20 Years” by disco ver magazine. Povinelli is also Project Director for the National Chimpanzee Observatory Working Group, a group of scientists, policy makers, and concerned citizens dedicated to creating a network of naturalistic observatories to prevent the imminent extinction of chimpanzees in captivity and preserve them for future behavioral and cognitive study.