One-Handed Motor Activity Does Not Interfere With Naming Lateralized Pictures of Tools

The motor interference hypothesis posits that performing a secondary motor task with a task relevant effector (e.g.. the hand) impairs performance on a primary object-naming task wherein objects are used by the same effector. However, evidence in favor of this hypothesis has been mixed. We sought to replicate findings from a lateralized object-naming paradigm, which supports the motor interference hypothesis, and to expand upon this previous research by also examining handedness. Across four experiments, we examined whether performance on a primary object-naming task is impaired by a secondary motor task where participants either squeezed a ball or continually moved their fingers in and out of a fist posture. We failed to observe any significant effects on either response times or error rates on the primary task. Furthermore, handedness did not influence performance on the primary task. Overall, our findings do not provide strong support for a functional role for motor neural resources in object naming. This could suggest that the motor activation that accompanies object recognition is a byproduct of this process. We also argue for a contextual rather than invariant activation of motor information in object processing tasks and discuss the implications of this view on theories of object conceptual representation.