Juicy fruit and creepy crawlies: An electrophysiological study of the implicit Go/NoGo association task

The Go/NoGo association task (GNAT) has been used in behavioral studies to measure the strength of association between different category groups and two poles of an evaluative dimension. However, reaction time data do not provide information about the neural time course of such associative information. We investigated event-related brain potentials (ERPs) elicited when participants were required to respond (Go) or withhold a response (NoGo) according to task instructions. Task instructions paired words from one of two taxonomic categories (fruit/bugs) with either pole of an evaluative dimension (good/bad). Within a given run, Go responses were assigned to one of the categories and one evaluative dimension. ERPs showed an increased negativity over frontal sites to NoGo as compared to Go responses. Moreover, NoGo minus Go difference waves showed that the N200 effect was delayed in trials within incongruent blocks (e.g., "Press if a bug word or a good word") as compared to trials within congruent blocks (e.g., "Press if a bug word or a bad word"). These results suggest that such associative attitude information is available at a very early stage of processing, less than 250 ms after seeing a fruit or a bug word. This finding is further discussed with respect to alternative explanations of the behavioral effect.