The effect of object state-changes on event processing: do objects compete with themselves?

Abstract

When an object is described as changing state during an event, do the representations of those states compete? The distinct states they represent cannot coexist at any one moment in time, yet each representation must be retrievable at the cost of suppressing the other possible object states. We used functional magnetic resonance imaging of human participants to test whether such competition does occur, and whether this competition between object states recruits brain areas sensitive to other forms of conflict. In Experiment 1, the same object was changed either substantially or minimally by one of two actions. In Experiment 2, the same action either substantially or minimally changed one of two objects. On a subject-specific basis, we identified voxels most responsive to conflict in a Stroop color-word interference task. Voxels in left posterior ventrolateral prefrontal cortex most responsive to Stroop conflict were also responsive to our object state-change manipulation, and were not responsive to the imageability of the described action. In contrast, voxels in left middle frontal gyrus responsive to Stroop conflict were not responsive even to language, and voxels in left middle temporal gyrus that were responsive to language and imageability were not responsive to object state-change. Results suggest that, when representing object state-change, multiple incompatible representations of an object compete, and the greater the difference between the initial state and the end state of an object, the greater the conflict.