Final answer:
The phenomenon that Gary experiences can be explained by social facilitation, where people tend to perform better on simple or well-learned tasks in the presence of others, but their performance declines on complex or unfamiliar tasks.
Step-by-step explanation:
The phenomenon that Gary experiences, where he suddenly forgets how to dance and his legs lose rhythm due to the presence of women staring at him and laughing, can be explained by social facilitation.
Social facilitation is the concept that suggests people tend to perform better on simple or well-learned tasks in the presence of others, but their performance declines on complex or unfamiliar tasks. In this case, dancing is a complex task for Gary, and the presence of the group of women becomes distracting and interferes with his ability to perform.
When a person feels observed and evaluated by others, especially in a situation that they might be judged on, it can cause anxiety and disrupt their performance, known as the social facilitation effect. This effect can impact both skilled and unskilled individuals, and it is influenced by factors like the task difficulty, audience size, and individual's level of self-confidence.