Exploring Brain Mechanisms Underlying Individual Differences in the Effect of Acquired Familiarity on Face Learning and Generalization

摘要

To transform frequently encountered unfamiliar faces into familiar ones is one of the most important social skills. Shyi & He (2011, CJP) recently demonstrated that multiple exposures with modest level of expression variation can jointly influence face learning and generalization. Here, using fMRI, we examined neural mechanisms that may underlie the effect of acquired familiarity of faces. Twenty-seven participants (19 female) performed a personality rating task to familiarize themselves with novel faces outside the scanner, where each face was repeatedly presented 20 times with expression variation. A face/person recognition test was then administered during the functional scan, and participants had to decide whether the test face belonged to someone they learned during the rating task. Faces of old target, new target, and distractors were shown, where old target refers a face image that was previously presented, new target refers to a face wearing an expression different from when it was originally presented, and the distractor faces were those never shown before. After the recognition task, participants performed a one-back task, while viewing either static images or dynamic videos for localizing the bilateral face-selective ROIs, including OFA, FFA, STS and inferior frontal gyrus (IFG). Participants were divided into two groups according to their generalization performance. Those who exhibited relatively strong generalization, in comparison to those exhibited relatively weak generalization, yielded greater activations in the left OFA, left FFA, right mSTS, right pSTS, and right IFG areas. Moreover, the correlations between the BOLD signal change of face-selective regions and face generalization indicated that neural activations in the left FFA, right mSTS, bilateral pSTS, and right IFG can predict the magnitude of generalization to new target faces. Taken together, these results highlight the neural mechanisms that may underlie individual differences in the effect of acquired familiarity on face learning and generalization.