Moving hand reveals dynamics of thought
- Department of Psychology, University of Connecticut, Storrs, CT 06269-1020; and Haskins Laboratories, 300 George Street, New Haven, CT 06511
Perception, cognition, and action occur over time. An organism must continuously and rapidly integrate sensory data with prior knowledge and potential actions at multiple timescales. This makes time of central importance in cognitive science. Crucial questions hinge on time, from the class of systems that may underlie cognition to debates about constraints on the functional organization of the brain and theoretical disputes in specialized domains. Often, the fine-grained time-course predictions that distinguish theories exceed the temporal resolution of available measures. In this issue of PNAS, Spivey et al. (1) introduce a method (“mouse tracking”) that provides a continuous measure of underlying perception and cognition in online language processing, promising badly needed leverage for addressing theoretical impasses, narrow and broad. I will describe examples of theoretical debates that hinge on time course, the difficulties in assessing time, and how the strengths and limitations of the new method complement current techniques for estimating time course. I conclude with a discussion of the potential of the new method to extend the tools and implications of dynamical systems theory (DST) to higher-level cognition.
The Time-Course Quandary
Precious little of perception and cognition can be observed directly and instead must be inferred from relationships between input and behavior, often from single postperceptual responses. A typical word-recognition paradigm is lexical decision. A subject sees or hears words and nonwords and hits keys indicating whether the stimulus was a word. The more frequently a word is used, the more quickly subjects respond yes; however, the more words that sound similar to it, the slower the response. So reaction times tell us a complex process of activation and competition underlies word recognition but indicate little beyond the approximate number of activated words and some of their characteristics. Theories make conflicting predictions about precisely which words are activated, and how …
