IT IS NOT WHAT YOU THINK IT IS: ERP CORRELATES OF VERBAL AND NON-VERBAL AMBIGUITY PROCESSING

Perceptual information is often ambiguous and we have to deal with such ambiguity to ensure optimal behavior; yet, the mechanisms that our brain uses for processing ambiguous stimuli are not well understood. In the current study, we tested whether there were any common markers of neural processing of ambiguity, regardless of its type. To this end, ERPs (event-related potentials) were elicited under similar experimental conditions by either verbal or non-verbal information: ambiguous fi gures vs verbal jokes. It has been suggested that ambiguous graphical information triggers a mismatch confl ict at earlier stages of processing, whereas in case of perception of ambiguous written texts, it takes place at later stages, associated with semantic analysis. Results of our experiment show that perception of both ambiguous figures and verbal jokes was related to semantic reversion, as the amplitude of the negative-going N400 component increased in response to both pictorial and verbal stimuli that were correctly identified as having more than one meaning, in contrast to otherwise similar but unambiguous control stimuli.