Spatial Attention in Visual Search for Features and Feature Conjunctions

Abstract

Spatial attention was measured in visual search tasks using a spatial probe Both speed and accuracy measures showed that in a conjunction task, spatial attention was allocated to locations according to the presence of target features Also, contrary to some predictions, spatial attention was used when a clearly distinguishable feature defined the target The results raise questions about any account that assumes separate mechanisms for feature and conjunction search The probe method demonstrated here allows a very direct measurement of attentional allocation, and may uncover aspects of selection not revealed by visual search