Modulation of the fusiform face area following minimal exposure to motivationally relevant faces: Evidence of in-group enhancement (not out-group disregard)

Studies have shown that fusiform face area (FFA) activity increases with visual expertise. We present an fMRI study showingthat faces from a social category made relevant by an experimental manipulation (members of an experimentally createdin-group) preferentially recruited the FFA even when they werematched in exposure to face stimuli from a less significant social category (members of an experimentally created out-group).Faces were randomly assigned to groups and fully counter balanced so that no perceptual cues allowed participants to visually distinguish category membership. The results revealed a pattern of in-group enhancement (not out-group disregard),such that the FFA was selectively engaged following the presentation of in-group compared with out-group or unaffiliated control faces even when the intergroup distinction was arbitrary,and exposure to in-group and out-group faces was equivalent and brief. In addition, individual differences in FFA activity forin-group versus out-group faces were correlated with recognitionmemory differences for in-group and out-group faces. Theeffects of group membership on the FFA were not affectedby task instruction to respond to in-group or out-group members and were functionally dissociated from early visual processing in the primary visual cortex. This study provides evidencethat the FFA is sensitive to top-down influences and may be involved in subordinate level (vs. super ordinate level) encodingof stimuli in the absence of long-term exposure or explicit task instructions.