The effect of uncertainty on category-specific attentional orientation was accommodated by shape- and color- dimension.

Abstract

Our attentional orientation to a particular object or category is influenced by uncertainty. However, it is still unclear how different forms of uncertainty affect category-specific attentional orientation (CAO). In order to investigate the neural mechanisms of uncertainty on CAO in different dimensions, a task combined with associative learning task and visual search paradigm was employed in two event-related potential (ERP) experiments, and the target was defined by shape (Experiment 1) or color category (Experiment 2). As the uncertainty regarding background information, the expectation was manipulated by the validity between auditory cue and target’s location. As the uncertainty regarding immediate sensory information, the perceptual load was manipulated by the homogeneity of distractors. The results showed that in the shape dimension (Experiment 1), a larger N2pc was elicited by invalid cues relative to valid ones, indicating the role of expectation on CAO. In the color dimension (Experiment 2), the interaction between expectation and perceptual load for cue - elicited N2pc showed an integrated effect of two forms of uncertainty on CAO. The findings supported an account of feature-based activation of category and an integrated processing of two uncertainties on CAO with sufficient resources.