Poster B130, Sunday, March 26, 8:00 – 10:00 am, Pacific Concourse
It's the Right Cue: Hemispheric Differences in Predictive Processing of Natural Scenes.
Manoj Kumar1, Yanqi Zhang1, Diane M. Beck1, Kara D. Federmeier1; 1University of Illinois at Urbana-Champaign
Imaging studies have revealed hemispheric asymmetries in the processing of natural scenes, with the left hemisphere (LH) showing sensitivity to scene category but not identity and the right (RH) showing sensitivity to both identity and category (Stevens et al., 2012). However, little is known about the processing dynamics underlying such asymmetries, including each hemisphere’s sensitivity to perceptual regularities and to contextual information that may be predictive of scene category. To address this, we manipulated both scene representativeness (good/bad exemplars) and expectancy (match/mismatch to a prior verbal category cue) and measured event-related potentials (ERPs) while participants viewed presentations, to the left visual field (LVF) and right visual field (RVF), of scenes from six categories: beaches, city streets, forests, highways, mountains and offices. Both hemispheres showed similar sensitivity to scene representativeness, with larger N300 responses (an ERP component linked to high-level perceptual processing) for bad than good exemplars. However, there were notable asymmetries in the time-course of sensitivity to cuing. With LVF (RH) presentation, cuing effects emerged early (150-200 ms), in the form of an enhanced P2 response to good scenes that mismatched (versus matched) the cues. In contrast, cuing effects for RVF (LH) presentation did not emerge until 300-350 ms, in the form of modulations of the N300 (smaller for good matches). The results suggest a RH superiority for using context to prepare perceptual templates in anticipation of upcoming scene information and rapidly matching those templates with incoming perceptual information.
Topic Area: PERCEPTION & ACTION: Vision