Tyree is lifting weights to build muscle for the upcoming football season. While in the gym lifting, a group of cheerleaders comes in to start practice. While the cheerleaders were watching, Tyree was able to do 10 reps more than he has ever accomplished in the past. This best illustrates .

Social Facilitation

Explanation:

SOCIAL FACILITATION is defined as the way in which an individual performance is well improved when they work with others because it triggers and motivates them to perform well rather than be alone due to the presence of other people watching them or when they are competing with others doing the same task which is why SOCIAL FACILITATION often increase the arousal level of an athlete due to the presence of an audience by enhancing their performance which is why Tyree was able to do 10 reps more than he has ever accomplished in the past.