Memory Bias toward Body Information in Women with Negative Physical Self:Evidence from an ERP Study

Abstract

Listen

Translate article

Behavior research evidence has shown that people with a negative physical self have a cognitive bias with a longer reaction time to body information than to information.Chen(2005) indicated that participants with a negative physical self have a cognitive preference and selectively perceived body information;however,the underlying mechanism of this phenomenon has not been discussed further.Therefore,the aim of this study is to reveal the brain mechanism of negative physical self by using the event-related potential(ERP) technique. ERPs were recorded to examine the electrophysiologic correlates of the recognition of body pictures.After completing the Negative Physical Self Scale(NPSS),based on their scores on the NPSS-Fat,28 participants were assigned to the control group(14 normal females) or experimental group(14 females with a negative physical self).During phase one,288 were presented to the participants.The participants were asked to respond when the target picture appeared.Phase two involved the random presentation of 576 pictures,which consisted of the 288 already presented in phase one and 288 new ones.The participants were requested to judge whether or not the had appeared in phase one.According to the participants' responses,the electroencephalography(EEG) of the responses to fat pictures, pictures, and neutral pictures was separately overlapped.The averaged epoch for an ERP was 1200ms including an epoch of 200ms for the pre-answer baseline. ERP waveforms of both groups showed that both and thin elicited a more positive ERP deflection than did in the time interval of 250~1000ms.Moreover,we found that the elicited a more positive ERP deflection than did the thin in the time interval of 750~800 ms only in the experimental group.A voltage map of the difference wave of the and thin showed strong activity in the central frontal region.The dipole analysis(brain electrical source analysis(BESA) software) localized the generator of the difference wave(fat minus thin pictures) in the right occipital lobe. In the current study,it is indicated that the difference wave of the and thin mainly activated the right inferior occipital gyrus,which was consistent with Uddin et al.'s(2005) functional magnetic resonance imaging(fMRI) findings that the same brain region was activated by images of one's own face.A possible interpretation might be that body information may have activated physical self-schema in participants with a negative physical self,which might be reflected by the activation of the right inferior occipital gyrus.