Dyadic interaction enhances sensitivity and shifts decision criterion in a change detection task

Can two-person decision-making change performance in detecting a change in the scene? Observers sometimes fail to detect visual changes that occur during a coincident visual transient or other disruption, a phenomenon known as change blindness. Although change blindness has been extensively studied, relatively little is known about whether collaborative decision-making can reduce such failures. Research on collective decision-making suggests that dyads make more accurate judgments than individuals, and recent findings show that they also adopt a more liberal decision criterion. This study examined whether dyads exhibit differences in sensitivity and decision criteria in a change detection task.

Participants in a dyad judged individually and collectively whether the pair of flickering images contained a change. We also conducted a follow-up independent repeated decision-making experiment, in which individuals responded twice with a period of time between two judgments, to confirm whether the second judgment without social input differed from the first judgment.

Results from the dyadic decision-making experiment showed that dyads demonstrated enhanced sensitivity to detect changes and were more likely to respond "change present" than better individuals, suggesting the dyadic decisions were not simply based on the judgment of the more sensitive member. Results from the follow-up experiment supported the effect of dyadic decision-making by indicating no difference in sensitivity and decision criterion between first and second judgments.

These findings suggest that dyadic decision-making may help reduce the failure of change detection by improving sensitivity and shifting the decision criterion to minimize missed detections.