The Effect and Time Course of Prediction and Perceptual Load on Category-Based Attentional Orienting Across Color and Shape Dimensions

TL;DR

This study explores how predictions and perceptual load influence attention to objects based on their color or shape over time.

Contribution

It reveals how prediction and perceptual load independently and interactively affect attentional orienting across different object dimensions.

Findings

Invalid predictions increase N2pc for shape-defined targets but not color-defined ones.

Prediction and perceptual load interact to affect behavioral accuracy in later processing stages.

Top-down and bottom-up factors modulate attention differently depending on object dimensions.

Abstract

Objectives: This study investigated the temporal dynamics of category-based attentional orienting (CAO) under the influences of prediction (top-down) and perceptual load (bottom-up) across color and shape dimensions, combining behavioral and event-related potential (ERP) measures. Methods: Across two experiments, we manipulated predictive validity and perceptual load during a visual search for category-defined targets. Results: The results revealed a critical dimension-specific effect of prediction: invalid predictions elicited a larger N2pc component (indexing attentional selection) for shape-defined targets, but not color-defined targets, indicating that shape CAO relies more heavily on predictive information during early processing. At the behavioral level, a combined analysis of the two experiments revealed an interaction between prediction and perceptual load on accuracy, suggesting their integration can occur at later stages. Conclusions: These findings demonstrate that prediction and perceptual load exhibit distinct temporal profiles, primarily independently modulating early attentional orienting, with their interactive effects on behavior being more nuanced and dimension-dependent. This study elucidates the distinct temporal and dimensional mechanisms through which top-down and bottom-up sources of uncertainty shape attentional orienting to categories.

Figures