A wrinkle in time: asymmetric valuation of past and future events.

A series of studies shows that people value future events more than equivalent events in the equidistant past. Whether people imagined being compensated or compensating others, they required and offered more compensation for events that would take place in the future than for identical events that had taken place in the past. This temporal value asymmetry (TVA) was robust in between-persons comparisons and absent in within-persons comparisons, which suggests that participants considered the TVA irrational. Contemplating future events produced greater affect than did contemplating past events, and this difference mediated the TVA. We suggest that the TVA, the gain-loss asymmetry, and hyperbolic time discounting can be unified in a three-dimensional value function that describes how people value gains and losses of different magnitudes at different moments in time.