Recent studies have demonstrated that external rewards can affect intrinsic motivation to perform an activity. Money tends to decrease intrinsic motivation, whereas positive verbal reinforcements tend to increase intrinsic motivation. This paper presents evidence that negative feedback and threats of punishment also decrease intrinsic motivation. Subjects solved puzzles during the first part of the experimental session, after which observations relevant to their intrinsic motivation were made. Subjects in the negative feedback condition were given more difficult puzzles to solve than were the controls so that they railed more frequently than the control subjects. Those in the high failure condition showed less intrinsic motivation following their puzzle-solving session than did control subjects. Subjects in the threat condition received an aversive buzzer each time they were unable to solve a puzzle, while the control subjects did not. Those subjects threatened with the buzzer showed less intrinsic motivation than control subjects. (Author/BW)