Although previous research in event-related potentials (ERPs) has focused on the conditions under which faces are recognized, less research has focused on the process by which face representations are acquired and maintained. In Experiment I, participants were required to monitor for a target "Joe" face that was shown amongst a series of distractor "Other" faces. At the half-way point, participants were instructed to switch targets from the Joe face to a previous distractor face that is now labeled "Bob". The ERP analysis focused on the posterior N250 component known to index face familiarity and the P300 component associated with context
updating and response decision. Results showed that the N250 increased in negativity to target Joe face compared to the Bob face and a designated Other face. In the second half of the experiment, a more negative N250 was produced to the now target Bob face compared to the Other face. Critical1y, the more negative N250 to the Joe face was maintained even though Joe was no longer the target. The P300 component followed a similar pattern of brain response where the Joe face elicited a significantly larger P300 amplitude than the Other and Bob face. In the Bob half of the experiment, the Bob face elicited a reliably larger P300 than the Other faces
and the heightened P300 to the Joe face was sustained. In Experiment 2, we examined whether the increased N2S0 negativity and enhanced P300 to Joe was due to simple naming effects. Participants were introduced to both Joe and Bob faces and names at the beginning of the experiment. During the first half of the experiment,
participants were to monitor for the Joe face and at the half-way point, they were instructed to switch targets to the Bob face. Findings show that N250 negativity significantly increased to the Joe face relative to the Bob and Other faces in the first half of the experiment and an increased N250 negativity was found for target Bob face and the non-target Joe face in the second half. An increased P300 amplitude was demonstrated to the target Joe and Bob faces in the first and second halves of the experiment, respectively. Importantly, the P300 amplitude elicited by the Joe face equaled the P300 amplitude to the Bob face even though it was no longer the target face.The findings from Experiment 1 and 2 suggest that the N250 component is not solely determined
by name labeling, exposure or task-relevancy, but it is the combination of these factors that contribute to the acquisition of enduring face representations. / Graduate
| Identifer | oai:union.ndltd.org:uvic.ca/oai:dspace.library.uvic.ca:1828/3334 |
| Date | 31 May 2011 |
| Creators | Gordon, Iris |
| Contributors | Tanaka, James William |
| Source Sets | University of Victoria |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Rights | Available to the World Wide Web |
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