According to Zajonc's theory, what effect does the presence of others have on an individual?

Zajonc's theory of social facilitation posits that the presence of others can increase an individual's arousal level, which in turn enhances the performance of dominant responses—those that are well-learned or instinctual for the individual. This means that when someone is in a social environment, their instinctive responses tend to become more pronounced. For example, an athlete may perform better at a well-practiced skill in front of an audience, while a less familiar task may suffer due to increased anxiety and arousal. The core idea is that while social presence can boost performance in areas where one is confident and skilled, it can also hinder performance in areas that require more focus or less practiced responses.

This understanding emphasizes the dual nature of social facilitation: it can promote enhanced performance for familiar tasks while potentially impairing performance for unfamiliar or complex tasks. Therefore, the increase in arousal in the presence of others is fundamental to Zajonc's explanation of how social dynamics impact individual performance.