Unconscious priming dissociates 'free choice' from 'spontaneous urge' responses

Advances in neuroscience offer the exciting prospect of understanding 'free' choices - the subject of the free will debate in philosophy. However, while physiological techniques and analysis have progressed rapidly to meet this challenge, task design has not. The challenge is now to develop laboratory tasks that adequately capture 'free' picking or choosing. To isolate 'internally' generated intentions from those impelled by external stimulus, observers are asked to 'choose freely' or to wait for a felt 'urge'. However, no previous work has explicitly distinguished between instructions that refer to 'urges' versus to 'choosing'. The philosopher Alfred Mele (e.g., 2009; 2014) has argued that the distinction is of crucial conceptual importance, but the two have not yet been empirically distinguished. Here, we show that conscious and unconscious, task-irrelevant primes, bias observers' binary choices when they are instructed to 'choose freely', not when they 'wait for an urge', underscoring the practical importance of Mele's conceptual distinction. Neuroscience must incorporate this distinction if we are to understand processes underpinning free choice.