Team composition has long been known to play a large role in the effectiveness of teams because it determines the amount of knowledge and skill team members have to apply to the team task—in terms of both task completion and working interdependently. Although surface-level differences in team composition (e.g., demographics) can affect team performance, deep-level characteristics such as intelligence and personality have been found to have larger impacts. Individual intelligence, also called cognitive ability, is the ability to perform cognitive tasks. Individuals with higher intelligence are better able to consistently perform cognitive tasks well. The same ability that enables individuals to perform well on individual cognitive tasks should also be relevant for similar cognitive tasks that are assigned to teams, so they are higher performers in job settings that require cognitive performance. Team output is therefore a function of the individual contributions of its members. The effects of personality, on the other hand, can vary depending on the specific context involved. Often, personality characteristics create patterns of behavior such that people high in a given personality trait tend to behave and respond to others in similar ways. When entering a new team without prior established practices, individuals' personalities will shape their initial behaviors in a new team and how they react to the behavior of others. The central tendency of members' behaviors will develop the team's common behaviors through shared interactions. For example, if many team members are high in extraversion, initial behaviors are more likely to be social and gregarious, and the response to those behaviors would be positive, social, and gregarious. The few team members lower in extraversion are likely to avoid challenging the emerging central tendency in behavior. Thus, team mean personality traits are highly impactful in forging group norms, shaping subsequent interactions between members.