One mirror effect: The regularities of recognition memory.

The mirror effect is a pattern of results generally found in two-condition recognition memory experiments that is consistent with normative signal detection theory as a model of recognition. However, the claim has been made that there is a distinct mirror effect, the "strength mirror effect," that differs from the normative one. This claim is based on experiments on recognition memory in which repetition or study time is varied to produce differences in accuracy, where typically the ordinary mirror effect pattern is absent. If this claim is correct, it has major implications for theories of recognition memory. Therefore, a full examination of the data that support the claim was called for. To do that, we replicated the basic demonstration of the no-mirror-effect data and analyzed it further in a series of experiments. The analysis showed the following: (1) Whether or not the mirror effect occurs is determined by whether the experimenter furnishes effective discriminanda that distinguish the weak and strong conditions for the participant. (2) Once Finding 1 is taken into account, no adjustments of or additions to the normative signal detection theory explanations are necessary. (3) There is only one mirror effect, and no separate "strength mirror effect."