Using Spatial Frequency Scales for Processing Face Features and Face Configuration: an ERP Analysis

In the present study we examined the influence of spatial filtering on the N170-effect, a relatively early face-selective ERP difference associated with face detection. We compared modulation of the N170-effect using spatially filtered stimuli that either facilitated feature analysis or impeded configural analysis. The salience of inner face components was enhanced by presenting them in isolation. Configural processing was manipulated by face inversion. The N170-effects elicited by upright faces and isolated inner components were similar across low- and high-spatial frequency scales. In contrast, the inversion effect (enhanced N170 amplitude for inverted compared with upright faces) was only observed with broadband and low-spatial frequency stimuli. These findings demonstrate that the N170-effect can be influenced by both low- and high-spatial frequency channels. Moreover, they indicate that different configural manipulations (isolated features vs. face inversion) affect face detection in distinct ways, consistent with separate processing mechanisms for different types of configural encoding.