Mistaking opposition for autonomy: psychophysical studies on detecting choice bias

Do people know when they act freely and autonomously versus when their actions are influenced? While the human aspiration to freedom is widespread, little research has investigated how people perceive whether their choices are biased. Here, we explored how actions congruent or incongruent with suggestions are perceived as influenced or free. Across three experiments, participants saw directional stimuli cueing left or right manual responses. They were instructed to follow the cue's suggestion, oppose it or ignore it entirely to make a 'free' choice. We found that we could bias participants' 'free responses' towards adherence or opposition, by making one instruction more frequent than the other. Strikingly, participants consistently reported feeling less influenced by cues to which they responded incongruently, even when response habits effectively biased them towards such opposition behaviour. This effect was so compelling that cues that were frequently presented with the Oppose instruction became systematically judged as having less influence on behaviour, artificially increasing the sense of freedom of choice. Taken together, these findings demonstrate that acting contrarian distorts the perception of autonomy. Crucially, we demonstrate the existence of a novel illusion of freedom evoked by trained opposition. Our results have important implications for understanding mechanisms of persuasion.