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Folk Physics for Apes The Chimpanzee's Theory of How the World Works by Daniel J. Povinelli Oxford University Press, Oxford, 2000. 407 pp. $85. ISBN 0-19-857220-4.
Research on cognitive evolution has has a contentious history. Many scientists have argued in favor of vast differences between humans and other animals, trumpeting our unique capacity to produce fire, art, music, and humor. In contrast, others have argued for the similarities by showing that we are not alone in our capacity to hunt, make tools, and navigate in a Machiavellian world of status striving and deceit. As the field has matured, however, it has become clear that all creatures, humans included, have evolved unique mental signatures, designed to solve the most significant problems of the past. Therefore, two of the most pressing questions are: How do human minds differ from the minds of other animals? And what selective pressures have led to such patterns over evolutionary time?
Folk Physics for Apes, written by anthropologist Daniel Povinelli, represents a recent contribution to this contentious history. In parallel with his views on social knowledge, Povinelli's bottom line is that chimpanzees think about the physical world in a way radically different from our own. Whereas humans can reason about imperceptible physical forces such as gravity, mass, and inertia, chimpanzees can only reason about perceptible things such as the learned association between dropping a rock onto a palm nut and then eating the fleshy meat inside. If Povinelli's conclusions are correct, our cognitive departure from nonhuman primates is even more dramatic than previously believed.
Folk is an unusual book in that none of the empirical work it presents has ever been peer reviewed. Povinelli discusses 27 experiments designed to reveal what chimpanzees know about physical objects, how they work, what their defining features are, and what they can be used for. Each study tested the same group or subgroup of seven chimpanzees, first as juveniles...