ABSTRACT
The brain uses repetitive sampling to analyze the complex stimuli with which it is confronted. “Taking a second look” is an understandable phrase because it describes a common and essential perceptual phenomenon. Although collecting successive samples of stimuli and extracting different information from them may be a routine operation, the machinery involved must be complex indeed, involving interaction and synchronization of activities in sensory and motor systems. Neurobiological studies of perception have treated sensory systems as passive entities responding to but not acting on input signals; computer models of brain systems have (with some notable exceptions) also used networks that process a relatively invariant signal, in an all-or-none fashion. Thus little is known about the roles played by physiological and anatomical characteristics of sensory systems in the analysis of sequentially sampled stimuli.
