Arousal level and exemplar variability of emotional face and voice encoding influence expression-independent identity recognition

Emotional stimuli and events are better and more easily remembered than neutral ones. However, this advantage appears to come at a cost, namely a decreased accuracy for peripheral, emotion-irrelevant details. There is some evidence, particularly in the visual modality, that this trade-off also applies to emotional expressions, leading to a difficulty in identifying an unfamiliar individual’s identity when presented with an expression different from the one encountered at encoding. On the other hand, past research also suggests that identity recognition memory benefits from exposure to different encoding exemplars, although whether this is also the case for emotional expressions, particularly voices, remains unknown. Here, we directly addressed these questions by conducting a series of voice and face identity memory online studies, using a within-subject old/new recognition test in separate unimodal modules. In the Main Study, half of the identities were encoded with four presentations of one single expression (angry, fearful, happy, or sad; Uni condition) and the other half with one presentation of each emotion (Multi condition); all identities, intermixed with an equal number of new ones, were presented with a neutral expression in a subsequent recognition test. Participants (N = 547, 481 female) were randomly assigned to one of four groups in which a different Uni single emotion was used. Results, using linear mixed models on response choice and drift-diffusion-model parameters, revealed that high-arousal expressions interfered with emotion-independent identity recognition accuracy, but that such deficit could be compensated by presenting the same individual with various expressions (i.e., high exemplar variability). These findings were confirmed by a significant correlation between memory performance and stimulus arousal, across modalities and emotions, and by two follow-up studies (Study 1: N = 172, 150 female; Study 2: N = 174, 154 female), which extended the original observations and ruled out some potential confounding effects. Taken together, the findings reported here expand and refine our current knowledge of the influence of emotion on memory, and highlight the importance of, and interaction between, exemplar variability and emotional arousal in identity recognition memory.