Confirmation bias and misconceptions: Pupillometric evidence for a confirmation bias in misconceptions feedback

•Disconfirming feedback regarding misconceptions produces a larger pupillary response compared to feedback confirming the misconception.•Ambiguous feedback produces an identical pupil response to clear confirming feedback, but only when the ambiguous feedback is positively framed.•Commitment towards the misconception was associated with stronger effects of confirming and disconfirming feedback on the pupillary response.•The findings support a confirmation bias in the maintenance of misconceptions and are in line with general models of inconsistency-compensation. It has long been supposed that the confirmation bias plays a role in the prevalence and maintenance of misconceptions. However, this has been supported more by argument than by empirical evidence. In the present paper, we show how different types of belief-feedback evoke physiological responses consistent with the presence of a confirmation bias. Participants were presented with misconceptions and indicated whether they believed each misconception to be true or false, as well as how committed they were to the misconception. Each response was followed by feedback that was either clear (i.e., “correct” or “incorrect”) or ambiguous (i.e., “partly correct” or “partly incorrect”). Pupillary response to each feedback condition was assessed. The results show an interaction between feedback accuracy and feedback clarity on pupil size. The largest pupil size was found in response to clear disconfirmatory feedback. The smallest pupil size was found in response to both clear and ambiguous confirmatory feedback. Crucially, the pupil responded to ambiguous confirmatory feedback as though it were wholly confirmatory. Moreover, pupil size in response to ambiguous disconfirmatory feedback was significantly smaller than response to clear disconfirmatory feedback, showing an overall trend towards confirmatory processing in the absence of clear disconfirmation. Additionally, we show a moderation by commitment towards the misconception. The greater the commitment, the larger the effect of belief-violating feedback on pupil size. These findings support recent theorizing in the field of misconceptions and, more generally, the field of inconsistency-compensation.