Using visual imagery to manipulate recognition memory for faces whose appearance has changed

Real-world recognition requires our memory system to accommodate perceptual changes that occur after encoding; for example, eyewitnesses must recognize perpetrators across changes in appearance. However, it is not clear how this flexible recognition ability can be improved: Standard encoding strategies not only tend to be ineffective, but can in fact be detrimental for recognizing people across appearance changes. Given the effectiveness of visual imagery in creating and modifying memory representations, we examined whether counterfactual visual imagery could be used to manipulate flexible recognition by simulating an increase in encoding-retrieval similarity. Across two experiments, participants (n = 317) encoded faces with neutral expressions and were cued to imagine the faces with either happy or angry expressions. During later retrieval, participants saw lineups of old and new faces with either happy or angry expressions, and selected the old face and provided recognition confidence. Old/new recognition discriminability and confidence were higher when a face's expression at retrieval matched the expression that it was imagined in during encoding (i.e., congruent imagery); interestingly, however, there was Bayesian evidence for no benefit of imagery congruence for face-choice accuracy. Moreover, congruent imagery improved recognition for old arrays irrespective of whether participants correctly selected the old face, suggesting that the imagery manipulation influenced a diffuse sense of recognition without influencing the ability to attribute that sense of recognition to a specific stimulus. Together, these findings indicate that visual imagery can directionally manipulate recognition for changed faces and produces a novel dissociation between old/new recognition and forced-choice accuracy.