Face-Specific Brain Mechanisms: Event-Related Potential (ERP) Evidence Suggesting the Degree of Activation is Modulated by Experimental Features

  • Rachel Doreen Grills


Two major theories regarding the specificity of certain brain regions in the perception of human faces have been put forth. The first, states an existence of a functional neural subsystem dedicated to the processing of human face forms (Farah, 1996). The other argues that this unique brain activity is in actuality a by-product of visual expertise, since similar patterns have been recorded during viewing of other stimuli classes to which the viewer has extensive experience (Gauthier & Curby, 2005). In review of the research, this essay contends that the level of brain activity involved in complex face perception is highly dependent on both image orientation and task demands; however the site of activity origin remains uniform across manipulations. The various experimental methodologies, including basic face-to-object comparisons, inversion effects and feature decomposition according to hierarchical salience, all produce similar results. The prominence of a negative waveform around 170 ms discriminated face processing from both animate and inanimate objects and remained present even with different stimuli orientation. The degree of this activity (i.e., amplitude) and temporal course (i.e., latency to onset) fluctuated as a function of experimental design; however continuity in neural location (i.e., fusiform gyrus and posterior area of the inferior-temporal) was maintained.