A postdictive illusion of choice.

Bear and Bloom report a simple experiment showing how we can feel as if we make a choice before the time at which this choice is actually made.

Do people know when, or whether, they have made a conscious choice? Here, we explore the possibility that choices can seem to occur before they are actually made. In two studies, participants were asked to quickly choose from a set of options before a randomly selected option was made salient. Even when they believed that they had made their decision prior to this event, participants were significantly more likely than chance to report choosing the salient option when this option was made salient soon after the perceived time of choice. Thus, without participants’ awareness, a seemingly later event influenced choices that were experienced as occurring at an earlier time. These findings suggest that, like certain low-level perceptual experiences, the experience of choice is susceptible to “postdictive” influence and that people may systematically overestimate the role that consciousness plays in their chosen behavior.

From their text:

In the first experiment participants viewed five white circles that appeared in random positions on a computer screen and were asked to try to quickly choose one of these circles “in their head” before one of the circles turned red. After a circle turned red, participants indicated whether they had chosen the red circle, had chosen a circle that did not turn red, or had not had enough time to choose a circle before one of them turned red.

Because the red circle is selected randomly on all trials, people performing this task should choose the red circle on approximately 20% of the trials in which they claim to have had time to make a choice if they are, in fact, making their choices before a circle turns red (and they are not biased to report choosing the red circle for some other reason). In contrast, a postdictive model predicts that people could consciously experience having made a choice before a circle turned red even though this choice did, in fact, occur after a circle turned red and was influenced by that event. Specifically, this could happen if a circle turns red soon enough to bias a person’s choice unconsciously (e.g., by subliminally capturing visual attention..), but this person completes the choice before becoming conscious of the circle’s turning red. On the other hand, if there is a relatively long delay until a circle turns red, a person would be more likely to have finished making a choice before even unconsciously processing a circle’s turning red; hence, this event would be less likely to bias the choice.

In a second experiment, we explored whether postdiction could occur in a slightly different paradigm, in which participants chose one of two different-colored circles. We used two, rather than five, choice options in this experiment to control for a worry that the time-dependent bias we observed in Experiment 1 could have been driven by low-confidence responding. If participants were less confident in choices they made more quickly, they might have been prone to choose relatively randomly between the “y” and “n” response options in short-delay trials. Such a random pattern of responding would have biased participants’ reports of choosing the red circle toward .50 (because there were only two response options), and would have resulted in greater-than-chance reports of choosing the red circle for these shorter delays (because chance was .20 in Experiment 1). By making chance .50 in this experiment, we eliminated any concern that random responding could yield the time-dependent pattern of bias that we observed in Experiment 1.