Poster #: 62
Topic: Memory and perception
Thursday, Sep 10, 2015
The vMMN is sensitive to within category and between category effect when using a morphing method
1Institute of Cognitive Neuroscience and Psychology RCNS HAS, Budapest, Hungary
2Institute of Cognitive Neuroscience and Psychology, RCNS, HAS, Budapest, Hungary
The aim of the study was to examine the event-related potential correlates of automatic face categorization processes. We supposed that the memory system underlying vMMN is capable of encoding categorical changes even if the eliciting stimuli are irrelevant to the ongoing task (the task was visual tracking). To this end in a passive oddball paradigm we explored the sensitivity of vMMN to within category or between categories deviancies. The stimuli were morphed female and male faces. We created six female-male gender-morph pairs with morph software. In the each of the pairs were chosen four morph- level stimuli. In the within category comparisons 100 per cent and 67 per cent female/male faces were presented in reverse control conditions, whereas in the between category comparisons the stimuli were 67-67 per cent female and male morphs. To avoid the specific physical effect of single faces, six pairs of morphs were created. The electrophysiological data showed that the deviant faces elicited a posterior negativity relative to the frequent standard ones. These effects are regarded as vMMNs generated by automatic detection of sequential regularities. Furthermore, the vMMN component in the between category sequences was larger than the vMMN in the within category sequences, even if the between and within category distances were similar. The results indicate that female and male information are encoded by different neural populations. According to the results, gender perception at an early stage of face processing does not require attentional processes, i.e., face gender categorical coding is automatic.