Quite reasonably, the editors’ charge was describing our most important contribution to psychology. Here, I draw morals for young people contemplating a career in psychological research.

Each scientist builds, through continued hard work and attention to detail, unique expertise and networks that elucidate several threads in the fabric of nature. Over a lifetime, these add up to a body of work. The first challenge budding young scientists face is settling on mysteries that are so interesting to them they want to spend their lives trying to explain them. Beginning as an undergraduate, my work has aimed at explaining how abstract concepts, such as infinity, life, matter, agent, cause, and others arise in the human mind.

Accounting for the human conceptual repertoire formidably challenges psychological science. Our genetic make-up and brains are remarkably similar to those of our nearest animal cousins, the great apes. Yet, we are the only animals that can ponder the causes and cures of cancer or of global warming, that can conceive orders of infinity – indeed, that can think any thoughts beyond the representational capacity of non-human animals. Moral 1. Find a scientific mystery that fascinates you. The mystery of human conceptual development structured my life's work.

As a biology major, my sophomore tutorial was taught by a postdoc working on bodily mechanisms that underlie biological clocks. What fascinated me was how scientists knew animals could tell time. My tutor guided me in reading the ethological literature of 1961: how omnivores learn what food to eat, how animals navigate, how infants recognize their mothers. At year's end, my tutor said, “Ethology IS a branch of biology, so you can do this kind of work as a biologist, but the future of biology is molecular biology. I believe that the deeper work on these kinds of issues will come from the new discipline of cognitive science, and highly recommend that you check it out.” Moral 2: Seek out good teachers, and follow their advice; good teachers have your interests at heart.

Junior year, I took a course on the nature of knowledge from three founders of cognitive science, George Miller, Jerome Bruner, and Noam Chomsky.

Overview

We argue that human reasoning is guided by a collection of innate domain-specific systems of knowledge. Each system is characterized by a set of core principles that define the entities covered by the domain and support reasoning about those entities. Learning, on this view, consists of an enrichment of the core principles, plus their entrenchment, along with the entrenchment of the ontology they determine. In these domains, then, we would expect cross-cultural universality: cognitive universals akin to language universals.

However, there is one crucial disanalogy to language. The history of science and mathematics demonstrates that conceptual change in cognitive domains is both possible and actual. Conceptual change involves overriding core principles, creating new principles, and creating new ontological types. We sketch one potential mechanism underlying conceptual change and motivate a central empirical problem for cognitive anthropology: To what extent is there cross-cultural universality in the domains covered by innate systems of knowledge?

Domain-Specific Cognition

The notion of domain-specific cognition to be pursued here is articulated most clearly by Chomsky (1980a). Humans are endowed with domain-specific systems of knowledge such as knowledge of language, knowledge of physical objects, and knowledge of number. Each system of knowledge applies to a distinct set of entities and phenomena. For example, knowledge of language applies to sentences and their constituents; knowledge of physical objects applies to macroscopic material bodies and their behavior; knowledge of number applies to sets and to mathematical operations such as addition.

Introduction

I take it as a given that the language we speak both reflects and shapes our conceptualization of the world. Theory changes, including changes in uitiveories, often involve the construction of a new language for describing some domain of phenomena, a language incommensurable with that which preceded it. On this view, sometimes theory learning involves the construction of a new representational resource, a new language not expressible or definable in the terms of the old one (Kuhn 1962, 1982; Feyerabend 1962; Kitcher 1978; Hacking 1993; but see Davidson 1974, and Fodor 1998, on the very coherence of the notion of conceptual change; see Carey 1985, 1988, 1991, for a defense of the notion and its application to theories of cognitive development).

Accepting the existence of genuine conceptual change in the course of cognitive development is tantamount to accepting the Whorfian hypothesis. After Black, scientists used a different language for describing thermal phenomena, one which led them to see phenomena such as heating and cooling, thermal expansion, and thermal equilibrium totally differently from the ways earlier scientists in an Aristotelian or Galilean tradition did (Wiser & Carey 1983); after Levoisier, scientists saw phenomena such as burning, and entities such as chemical compounds and air, totally differently from the ways scientists who held the phlogiston theory did (Kitcher 1978; Kuhn 1982). There is a long history of attempts to decide the debates between continuity and Whorfianism with a priori arguments.

The concept of death is emotionally charged and cognitively challenging. Understanding that all people die, that death is the inevitable end of the life cycle of each living individual, is fundamental to our understanding of ourselves as human beings. Conceptualizing and accepting death has consequences for how we live our lives as well as for how we manage our health. For these reasons, twentieth-century psychologists of many different theoretical persuasions – Freudians, Piagetians, educators, health psychologists – have described young children's grappling with the concept of death. These studies have documented in great detail the ways in which preschool children conceive of death differently from their elders, and the steps they take in approximating adult understanding.

Overview

We argue that human reasoning is guided by a collection of innate domain-specific systems of knowledge. Each system is characterized by a set of core principles that define the entities covered by the domain and support reasoning about those entities. Learning, on this view, consists of an enrichment of the core principles, plus their entrenchment, along with the entrenchment of the ontology they determine. In these domains, then, we would expect cross-cultural universality: cognitive universals akin to language universals.

However, there is one crucial disanalogy to language. The history of science and mathematics demonstrates that conceptual change in cognitive domains is both possible and actual. Conceptual change involves overriding core principles, creating new principles, and creating new ontological types. We sketch one potential mechanism underlying conceptual change and motivate a central empirical problem for cognitive anthropology: To what extent is there cross-cultural universality in the domains covered by innate systems of knowledge?

Domain-specific cognition

The notion of domain-specific cognition to be pursued here is articulated most clearly by Chomsky (1980a). Humans are endowed with domainspecific systems of knowledge such as knowledge of language, knowledge of physical objects, and knowledge of number. Each system of knowledge applies to a distinct set of entities and phenomena. For example, knowledge of language applies to sentences and their constituents; knowledge of physical objects applies to macroscopic material bodies and their behavior; knowledge of number applies to sets and to mathematical operations such as addition. More deeply, each system of knowledge is organized around a distinct body of core principles.