Abstract
Previous studies have shown that the observer's own face elicits speeded responses in behavioral tasks and generates a pattern of brain activity that is differentiated from other familiar stimuli. Studies employing event-related potentials (ERPs) have shown that when participants are monitoring for a novel target face, the presentation of their own face elicits an enhanced negative brain potential in posterior channels approximately 250 ms after stimulus onset. Here, we examine whether the own-face N250 effect generalizes to other self-referential objects, specifically, images of the participant's own dog and own car. In our experiments, participants were asked to monitor for a target face (Joe), a target dog (Experiment 1: Joe's Dog) or a target car (Experiment 2: Joe's Car). The target face and object stimuli were presented with non-target foils that included novel face and object stimuli and self-referential stimuli, the participant's own face, their own dog (Experiment 1) and their own car (Experiment 2). Our results showed that an enhanced N250 negative potential was elicited by the target face and the target objects relative to the novel non-target faces and objects. The time course for target faces and target objects differed. Whereas the N250 to the target Joe face accrued gradually, the N250 to the target Joe dog and Joe car was evident in the first block. Importantly, the participant's own face, own dog, and own car produced an N250 potential that was equal in magnitude to the target stimuli. Thus, similar to the ERP response to the participant's own face, self-referential objects evoked an N250 response that did not differ from recently familiarized faces and objects. These results support the prepotency of self-relevant stimuli that readily command the observer's attention and spontaneously elicit an enhanced neural response that is independent of the stimulus' target status.
James S. McDonnell Foundation, the National Science Foundation (#SBE-0542013), the National Institutes of Health and the National Sciences and Engineering Research Council of Canada.