Abstract
Both blocked (Gauthier et al, 2000) and event-related (Xu et al, 2001) designs reveal significant BOLD activation in middle fusiform and lateral occipital gyrus for domains of expertise (e.g., birds and cars). That is, effects of expertise are observed in the same functionally-defined regions of interest (ROIs) associated with face processing. In addressing whether expertise recruits the same neural mechanisms as faces, two recent studies (e.g., Grill-Spector et al, 2004; Rhodes et al, 2004) have used stimuli drawn from the object class for which participants were experts, but not from their particular subordinate knowledge domain (e.g., antique cars for modern car experts and foreign butterflies/moths for native Lepidoptera experts). It is possible that such studies were subject to an “other-race” effect in expertise. We examine whether this manipulation contributed to findings that nominally argue against an “expertise account” for face-selectivity in ventral-temporal cortex. We compared the neural response in functionally defined face-selective ROIs for Rhode Island (RI) bird experts or novices while they viewed RI and Asian birds. Participants performed four different judgments depending on block: 1-back identity, 2-back identity, 1-back location, and passive viewing. For bird experts in both the passive viewing and 1-back location conditions, we observed little difference in the BOLD responses to RI and Asian birds, but a stronger response for RI as compared to Asian birds in the 1-back and 2-back identity conditions. In contrast, across all face-selective ROIs, bird novices showed similar neural responses for RI and Asian birds. This three-way interaction between task, stimulus familiarity, and expertise may account for apparent disparities in the literature, as well as generally demonstrating the multifaceted nature of face and object processing in the ventral pathway.
Funded by the Perceptual Expertise Network (#15573-S6), a collaborative award from James S. McDonnell Foundation, and NSF award #BCS-0094491.