Only irrelevant angry, but not happy, expressions facilitate the response inhibition.

It has been debated that arousal rather than valence modulates the response-inhibition process. The processing of irrelevant information of happy and angry faces interacts with attention differently. In the present study, arousal-matched irrelevant happy and angry faces were used as stop-signals in the stop-signal paradigm. Participants were required to respond to go-signals (discriminate between X or O). Occasionally, a stop-signal was presented where participants were required to withhold their motor response. Results indicate a significant effect of emotion on response inhibition, which suggests that valence of a stop-signal modulates inhibitory control. More specifically, we found that only irrelevant angry, but not happy, expressions facilitate the response inhibition process. These results have theoretical implications for understanding the nature of emotions and its interaction with cognitive control functions.