Electrophysiological correlates of local-global visual processing in college students with schizotypal traits: An event-related potential study

We examined local-global visual processing in college students with schizotypal traits using event-related potentials (ERPs). Local-global processing was assessed using a divided-attention task, in which large numbers (global level) composed of small numbers (local level) were presented. The control group had faster response time (RT) and more accurate responses to global-level than to local-level stimuli, whereas RT and accuracy did not differ between levels in the schizotypal-trait group. N150 amplitudes for local stimuli were larger than those for global stimuli in the schizotypal-trait group, whereas N150 amplitudes did not differ between levels in the control group. P300 amplitudes for local stimuli were larger relative to global stimuli in the control group, whereas P300 amplitudes did not differ between levels in the schizotypal-trait group. These results indicate that the global precedence effect was reduced in the schizotypal-trait group, possibly because of local-biased visual processing or difficulty in global processing.