This is the tendency for people to perform better on tasks in the presence of others than when alone.
Social facilitation refers to the phenomenon where individuals perform differently when in the presence of others than when alone, often improving on simple tasks due to increased arousal.
Robert Zajonc's research (1965) is pivotal for social facilitation, demonstrating that the presence of others boosts arousal, which enhances performance on well-learned tasks but may hinder complex new tasks.