Fear perception: can objective and subjective awareness measures be dissociated?

Whereas previous studies of fearful-face perception have probed visual awareness according to either objective or subjective criteria, in the present study, we probed the perception of briefly presented and masked fearful faces by assessing both types of perception within the same task. Both objective and subjective sensitivity measures were assessed within a common signal detection theory framework. To evaluate single-participant awareness, we employed a nonparametric receiver operating characteristic (ROC) analysis of the behavioral data, which involved collecting a large number of trials over multiple sessions. Our findings revealed that nearly all subjects could reliably detect 17-ms fearful-face targets, thus exhibiting above-chance objective perception at this target duration. Reliable subjective sensitivity was also observed for 33-ms fearful-face targets and, for some subjects, even for 17-ms targets. The analysis of single-session data suggests that previous experiments may have lacked sufficient statistical power to establish above-chance performance. Taken together, our findings are consistent with a dissociation of fear perception according to objective and subjective criteria, which could be assessed for each individual participant. The determination of such a dissociation zone may help in understanding the conditions linked to aware and unaware fear perception.