Volition motivates cognitive performance at the response-execution level by attenuating task-irrelevant motor activations

Humans express volition by making voluntary choices which, relative to forced choices, can motivate subsequent cognitive performance. However, it is unclear how underlying cognitive processes are facilitated by voluntary choice-making. In five experiments (total N = 188), participants were free or forced to choose a task-irrelevant picture from two alternatives, and then completed a conflict task, i.e., Flanker, Stroop, Simon, Stroop-Simon, or Flanker-Simon task, where the conflict effect could occur at different processing levels. Responses in all tasks were generally faster after voluntary (vs. forced) choices. Importantly, the conflict effect at the response-execution level, but not at the pre-response or response-selection level, was reduced by the voluntary choice-making. Model fitting revealed that the peak amplitude of automatic motor activations in the response-execution conflict was smaller after voluntary (vs. forced) choices. These findings suggest that volition motivates subsequent cognitive performance at the response-execution level by attenuating task-irrelevant motor activations.