Executive Function as an Interaction-Dominant Process

Traditional theories of psychology define the cognitive system as composed of insular, encapsulated components, controlled by a central executive. An alternative hypothesis suggests that cognitive control arises from the complex interaction among temporal scales of activity within the system. We examined the hand motions of preschool-age participants gathered during an executive-function task, card sorting, for evidence of multiplicative interactions across temporal scales. The time series of hand motions were submitted to iterated amplitude adjusted Fourier transformation (IAAFT), a surrogate data analysis technique that removes nonlinear, multiscale dependencies while preserving the linear structure of the time series. We found that removing multiscale effects via IAAFT led to a significant change in the width of the multifractal spectrum, an indicator of multiplicative interactions. The results suggest that cognitive control may arise from the interactions among temporal scales of activity within the system rather than as the result of a central executive.