The brain’s ability to make predictions has long been of interest to cognitive neuroscientists, who have used techniques including electroencephalography (EEG) to study this phenomenon. A component of neurophysiological activity, termed the Semantic Predictive Potential (SPP), may be an indicator of people’s ability to predict the nature of upcoming semantic content. Interestingly, a body of theoretical and experimental work suggests that people with schizophrenia and people who regularly use cannabis have difficulty making predictions about information in their environments. We explored how schizophrenia-like traits and cannabis use affected the SPP. Participants read sentences which differed in the predictability of their endings while brain activity was monitored using EEG. Participants then completed questionnaires assessing their levels of schizophrenia-like traits and cannabis use. We replicate previous findings suggesting that the SPP is sensitive to semantic predictability, and show that schizophrenia-like traits and cannabis use interact with semantic predictability to influence the SPP.
