Modulation of Brain Activity by the Integration of Color into Dorsal Stream Object Files

Two superimposed surfaces of dots are perceived as separate objects when rotating in two different directions. When one surface is cued, there is a larger suppression of the attentional ERP components of the unattended surface than the attended surface when two objects are perceived versus when one object is perceived. We hypothesized that the strength of object-based attention was dependent on the differentiation of the two object representations. We tested this hypothesis by determining if two oppositely rotating superimposed surfaces of differing colors would produce a greater cueing effect than if the two surfaces were the same color. This additional color feature would allow for object files with stronger neural representation, leading to a greater suppression of the uncued surface in the task. It was found that there was a greater cueing effect in the bicolored condition compared to the unicolored condition both behaviorally and in event related potentials.