There is a new Research Report by WP Banks and EA Isham, We Infer Rather than Perceive the Moment We Decided to Act (here). I have divided this subject in two and this is the second part dealing with their conclusions.
On the contrary, we propose that the reported W (reported time when action was consciously initiated) is not uniquely determined by any generator of the RP (EEG readiness potential). Rather, W is the time participants select on the basis of available cues, chief among them being the apparent time of response. Eagleman (2004) suggested that the critical cue for judgment of intention is perception of the response, thus reversing the assumed causal relation between intention and action. Here, we report an explicit test of this hypothesis.
A seminal experiment found that the reported time of a decision to perform a simple action was at least 300 ms after the onset of brain activity that normally preceded the action. In Experiment 1, we presented deceptive feedback (an auditory beep) 5 to 60 ms after the action to signify a movement time later than the actual movement. The reported time of decision moved forward in time linearly with the delay in feedback, and came after the muscular initiation of the response at all but the 5-ms delay. In Experiment 2, participants viewed their hand with and without a 120-ms video delay, and gave a time of decision 44 ms later with than without the delay. We conclude that participants’ report of their decision time is largely inferred from the apparent time of response. The perception of a hypothetical brain event prior to the response could have, at most, a small influence.
We do not take our findings to indicate that conscious intention has no role in behavior, but rather that the intuitive model of volition is overly simplisticit assumes a causal model by which an intention is consciously generated and is the immediate cause of an action. Our results imply that the intuitive model has it backwards; generation of responses is largely unconscious, and we infer the moment of decision from the perceived moment of action.