Time flies when you're having approach-motivated fun: effects of motivational intensity on time perception.

Time flies when you're having fun, but what is it about pleasant experiences that makes time seem to go by faster? In the experiments reported here, we tested the proposal that approach motivation causes perceptual shortening of time during pleasant experiences. Relative to a neutral state or a positive state with low approach motivation (experiment 1), a positive state with high approach motivation shortened perceptions of time. Also, individual differences in approach motivation predicted shorter perceptions of time. In experiment 2, we manipulated approach motivation independently of the affective state and showed that increasing approach motivation caused time to be perceived as passing more quickly. In Experiment 3, we showed that positive approach motivation, as opposed to arousal, shortens perception of time by comparing a highly arousing positive state with a highly arousing negative state. Shortening of time perception in appetitive states may prolong approach-motivated behavior and increase the likelihood of acquiring appetitive objects or goals.