INTRODUCTION

What are thoughts made of? Do we think in pictures? In words? In symbols? What is the currency of human cognition and how do the representations that make up thinking come to be in our minds? In this chapter, we explore the rich sources of input that humans receive from perception and language and how combining information from these two input streams can be used to create the amazing complexity and sophistication of the human knowledge system.

Cognitive science is often seen as emerging from the confluence of two research programs: Chomsky's nativist critique of behaviorist learning theories and the rise of artificial intelligence. Together these two tides lead to a seemingly inevitable pair of conclusions: we think in language-like symbols, and the primitive symbols used in thought are innate. If we think in innate language-like symbols, then obviously we do not think in English, or Russian, or Kuuk Thaayorre. Instead, we think in the universal language of thought – Mentalese” (Fodor, 1975). This conclusion has been explicitly defended by some in cognitive science, but more often it is an unarticulated background assumption. For example, in the literature on concepts and categorization, conceptual representations are often described using structured lists of linguistically labeled features, and researchers rarely suggest that the words used in their theories correspond to mental representations that are radically unlike words.

Which words do children learn earliest, and why? These questions bear on how humans organize the world into semantic concepts, and how children acquire this parsing. A useful perspective is to think of how bits of experience are conflated into the same concept. One possibility is that children are born with the set of conceptual conflations that figures in human language. But assuming (as we will) that most semantic concepts are learned, not innate, there remain two possibilities. First, aspects of perceptual experience could form inevitable conflations that are conceptualized and lexicalized as unified concepts.

In this case, we would have cognitive dominance: concepts arise from the cognitive-perceptual sphere and are simply named by language. A second possibility is guistic dominancee world presents perceptual bits whose clumping is not pre-ordained, and language has a say in how the bits get conflated into concepts. We propose that both cognitive and linguistic dominance apply, but to different degrees for different kinds of words (Gentner 1981, 1982). Some bits of experience naturally form themselves into inevitable (preindividuated) concepts, while other bits are able to enter into several different possible combinations.

Relational relativity and the division of dominance

Embracing both cognitive and linguistic dominance may seem to be a vague middle-of-the-road position. But we can make the distinction sharper by asking which applies when. We suggest a larger pattern, a division of dominance (Gentner 1988). The Division of Dominance continuum is shown in figure 8.1. At one extreme, concrete nouns - terms for objects and animate beings - follow cognitive- perceptual dominance.