Do You See the Forest or the Tree? Neural Gain and Breadth Versus Focus in Perceptual Processing

Abstract

When perceiving rich sensory information, some may integrate its various aspects, while others may selectively focus on its most salient aspects. We propose that neural gain modulates the tradeoff between breadth and selectivity, such that high gain focuses perception on those aspects of the information that have the strongest, most immediate influence, whereas low gain allows broader integration of different aspects. We illustrate our hypothesis using a neural network model of ambiguous letter perception. We then show experimentally that, in line with the model, pupil-diameter indices of high gain are associated with letter perception that is more selectively focused on the letter’s shape, or if primed, its semantic content. Finally, we use a recognition-memory experiment to show that the relationship between gain and selective processing also applies when the influence of different stimulus features is voluntarily modulated by task demands.