An ERP study of change detection, change blindness, and visual awareness

Authors


  • This study was supported financially by the Academy of Finland (project numbers 45704 and 47238). We thank Minna Lehtonen for running the experiment.

Address reprint requests to: Mika Koivisto, Centre for Cognitive Neuroscience, University of Turku, FIN-20014 Turku, Finland. E-mail: mika.koivisto@utu.fi

Abstract

Electrophysiological correlates of change detection and change blindness were studied in 12 observers. The ERP difference between detected changes and undetected changes was considered an electrophysiological correlate of visual awareness. Two distinct electrophysiological responses correlated with the awareness of change. First, awareness was associated with a negative amplitude shift at posterior sites around 200 ms after the change in the stimulus. The latency of the negative shift varied as a function of the task difficulty and the speed of becoming aware of the change. Second, ERPs to detected changes became more positive as compared with undetected changes around 400 ms after the change in the stimulus, peaking at parietal sites. We suggest that the earlier negativity is associated with a change in the content of visual awareness, whereas the later positivity may reflect more global processes needed in decision making and action planning.

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