Innateness, Learning, and Rationality.

J. P. Spencer et al. (2009) ask readers to reject the nativist–empiricist dialogue and adopt a new theoretical perspective on cognition, focusing on ‘‘developmental process.’’ This commentary argues that the dialogue between nativism and empiricism is a rich source of insight into the nature and development of human knowledge. Indeed, the dialogue is entering a new and exciting phase, in which new methods of controlled rearing and of cognitive neuroscience, and new conceptual tools for understanding learning, allow exploration of how human concepts emerge through the interaction of innate cognitive structures shaped by natural selection, with statistical learning processes shaped by specific encounters with the world. This approach fosters new, interdisciplinary research that promises to increase dramatically understanding of human knowledge. KEYWORDS—nativism; empiricism; cognitive development; core knowledge; Bayesian learning; controlled rearing Humans develop knowledge with remarkable speed and flexibility. Our reasoning about the physical world begins in infancy yet is continually revised in physics labs. Understanding of the social world grows rapidly throughout early development and takes on myriad forms across cultures. Knowledge of number and geometry has foundations in infancy yet develops to widely differing endpoints within and across societies. What accounts for the speed and flexibility of developing human knowledge? For 2,500 years, this question has animated the dialogue between nativism and empiricism. Nativist and empiricist claims This study was supported by National Institutes of Health Grant 23103 to E.S.S. Correspondence concerning this article should be addressed to Elizabeth Spelke, Laboratory for Developmental Studies, Department of Psychology, Harvard University, Cambridge, MA 02138; e-mail: [email protected]. a 2009, Copyright the Author(s) Journal Compilation a 2009, Society for Research in Child Development Volume 3, Number are in dialogue, not debate, for three reasons. One reason is semantic: Innate means not learned, and so claims of innateness and learning are mutually dependent. The second reason is conceptual: Any learning mechanism necessarily requires unlearned abilities for detecting and analyzing inputs and for drawing inferences, and so claims of learning inevitably presuppose a set of innate capacities. The third reason is empirical: People absorb systems of culture-specific knowledge largely by learning those systems. Although it is logically possible that exposure to French could cause children to speak Swahili, or courses in painting could cause students to know calculus, as a matter of fact, the relevant experience for developing knowledge of French and calculus includes exposure, respectively, to French and calculus. Thus, dialogue concerning what is learned, and what innate structures support that learning, requires consideration of the relevant experiences that allow for knowledge to be acquired. Spencer et al.’s (2009) article ‘‘Short Arms and Talking Eggs: Why We Should No Longer Abide the Nativist–Empiricist Debate’’ centers on two incompatible claims. In the introduction and conclusion, the authors argue that any claim of innateness is meaningless. In their discussion of examples, however, they argue that specific claims of innateness are not logically incoherent but false, and they draw with approval on evidence that children learn to recognize their caregivers, navigate through the environment, and speak their language. If learning is a coherent and useful concept in these domains, however, then claims of innateness also are coherent, useful, and necessary to explain the mechanisms underlying learning. We could contest Spencer et al.’s specific accounts of development in the above domains, but such a discussion is undermined by their more radical claim that the nativist–empiricist dialogue is a meaningless exercise. Thus, in this commentary, we consider the radical claim of Spencer et al.’s title, introduction, and conclusion. In place of the nativist–empiricist dialogue, Spencer et al. call for a new theoretical perspective that focuses on ‘‘developmental process.’’ Historians of science appraise theoretical perspectives in multiple ways, but there are two key criteria. First, does a perspective promote understanding of currently known phenomena and thinking about current problems? Second, does it foster new