Speaker:

Prof. Guy VanOrden

Title:

"Pink Noise, Power Laws, and Cognitive Performance"

Abstract

A growing body of studies find the pattern of pink noise (1/f noise) in trial series of response times from cognitive tasks. Tasks include simple reaction time, word naming, classification with memory load, mental rotation, lexical decision, serial and parallel visual search, repeated production of a spatial interval, and repeated judgments of an elapsed time. New experiments demonstrate that the slow tails of response time distributions are well described by power laws. These are phenomena associated with self-organized criticality. Self-organized criticality implies a system whose components are tightly vertically coupled--interactions between components dominate components' intrinsic dynamics. Traditional cognitive psychology assumed loose horizontal coupling whereby components' intrinsic dynamics dominate interactions between components. Loose horizontal coupling assumes that cognitive processes follow linearly one after the other on the time scale of a flowchart. Instead, cognitive processes appear to live on multiple time scales that are vertically coupled in cognitive performance.