Action Intentions Shape Task- and Phase-Specific Integration of Object Features

Theories of object-based attention suggest that attending to an object binds its features together. Yet, there is a growing body of work to suggest that the intention to grasp an object can alter the representation of features such that they are separately represented during different stages of motor planning and execution, whereas some object features such as shape and size might form integrated representations when afforded by motor control. However, it remains untested whether these features were integrated as an outcome of the requirements of grasping motor control, or due to attention towards the object in general. Therefore, here we investigated how task-relevancy modulates the integration of grasp-relevant object features. To this end, we recorded electroencephalography while human participants grasped or reached for objects that varied in their orientation and size. Using multivariate analyses, we found a superadditive integration of object orientation and size during action planning for grasping but not reaching. These integrated representations likely facilitated the calculation of stable grasp points as further evidenced by the representations of grasp-specific visual size and grip size emerging at similar times. Our results provide novel insights into the vital role of action intention on cognitive representations in the human brain.