TOEFL Reading: ETS-TOEFL阅读机经 - WPZ6B3IRJHZ73SQKL$

A person's performance on tasks can be influenced by the presence of other people, whether observers or coworkers. A. When people are present, the performance of individuals generally improves on tasks they already do well but worsens on tasks they generally do poorly. B. Studies show that bicycle racers pedal faster when they are competing against other racers, but children wind fishing reels slower when in the presence of others than when alone. C. People's performance on a task is more affected by the presence of others when those others are engaged in the same task than when the others are passive spectators. D. When people work together on a common task but no one's contribution is measured, there is a tendency for individuals to work less hard than if they were working alone. E. Social loafing decreases under certain conditions, such as when the performance of the group or its members is evaluated or when a positive outcome matters to the participants. F. While social loafing occurs in almost all groups across cultures, the extent to which it occurs in any particular group depends on the individual personalities of the group's members.