Visual Prediction of Novel Objects as a Function of Preparation Time, Temporal Expectancy, and Hemispheric Lateralization
Cybelle M. Smith1, Kara D. Federmeier1; 1University of Illinois, Urbana-Champaign
When and how does the brain make use of contextual information to facilitate visual object perception? We recorded EEG while participants (N=72) learned paired associations between scenes and novel objects from novel object categories. At test, scenes were presented and, after a delay, a matching or mismatching object appeared. We previously showed that varying the amount of scene preview time at test affects the time course of predictive facilitation for the object. Long (2500ms), vs. short (200ms), preparation times induced a latency advance in the LPC and the appearance of a fronto-central N300 match effect. We (N=36) replicated these findings using a parametric, within-subjects design, by randomly varying the scene preview duration (0-2500ms). LPC match effect amplitude increased and latency decreased with increased preparation time, consistent with earlier results. However, graded effects of match (assessed using mismatching objects that were similar to a match, both visually and in terms of their distribution across contexts) were attenuated or absent, suggesting a role for temporal expectation in graded contextual prediction. We next used lateralized presentation with a long scene preview (2500ms; N=36) to explore whether the cerebral hemispheres differentially contribute to visual object prediction. Right hemifield presentation, but not left, induced sensitivity to close vs. ‘impossible’ mismatches at fronto-central sites (onset ~350ms). Findings suggest knowing when and where a visual object will appear helps us to anticipate it, and the left hemisphere is better able to use category-level information to form graded visual predictions.
Topic Area: LONG-TERM MEMORY: Priming