Abstract
Evidence exists for a face processing network that includes areas of the frontal and temporal lobes. Temporal areas have been more widely studied in face perception; research on the frontal lobes has been mainly correlational. The current study aimed to investigate the role of frontal areas in face processing using behavioral experimental methodology. In Experiment 1, we used a face working memory (WM) load to overload the prefrontal cortex in healthy participants while they performed a same/different discrimination task on morphed faces and cars of varying difficulty. Results showed that on face discrimination trials, subjects made more false alarms (FAs) with versus without the face WM load, whereas car discrimination was unaffected (p < .01). This suggests that the resources needed for face discrimination may have been consumed by the face WM load. Experiment 2 took this one step further by investigating where these resources may be located. To eliminate the frontal memory component in Experiment 2, the faces held in memory in Experiment 1 were moved to the same screen as the discrimination task, thus serving as perceptual distractors. The results of Experiment 2 no longer showed more FAs on face compared to car trials (p > .10), which suggests that the difference in FAs between face and car trials found in Experiment 1 was due to the overload of frontal-dependent face discrimination resources by the face WM task. Additionally, the Experiment 2 results showed a significant decrease in hits on faces compared to cars when the distractors were present (p < .01), which we interpret as response interference. These results together are the first to experimentally implicate the frontal lobe in face perception. The question remains, however, whether this frontal involvement is specific to faces or if it is part of a general expertise network. A third experiment investigates this possibility.