Response bias modulates the confidence-accuracy relationship for both positive identifications and lineup rejections in a simultaneous lineup task

In recent years, the use of calibration analysis and confidence-accuracy characteristic analysis has revealed the confidence-accuracy relationship for positive identification (ID) made from a lineup is often strong. At the same time, the confidence-accuracy relationship for lineup rejections is typically much weaker. Why the relationship is often weak for lineup rejections remains unclear. Here, we report two experiments testing a prediction that follows from signal detection theory. Specifically, this theory predicts that one determinant of the strength of the confidence-accuracy relationship for both positive IDs and lineup rejections is response bias. Theoretically, inducing a more conservative response bias should weaken the confidence-accuracy relationship for positive IDs while strengthening it for lineup rejections. The two experiments reported here support this prediction.