Processing polarity: ERP evidence for differences between positive and negative polarity

► Negative and positive polarity items are processed in different ways. ► Difficulties with negative polarity items elicited an N400 effect. ► The N400 effect for NPIs might be interpreted as reflecting local semantic processing. ► Difficulties with positive polarity items elicited a P600 response. ► The P600 effect for PPIs might reflect a search for an appropriate broader affirmative context.