First Impressions or Good Endings? Preferences Depend on When You Ask

Rewards often unfold over time; we must summarize events in memory to guide future choices. Do first impressions matter most, or is it better to end on a good note? Across nine studies (N=569), we tested these competing intuitions and found that preferences depend on when rewards occur and when we are asked to evaluate an experience. In our “garage sale” task, participants opened boxes containing sequences of objects with values. All boxes were equally valuable, but rewards were either evenly distributed or clustered at the beginning, middle, or end of the sequence. First, we tested preferences and valuation shortly after learning; we consistently found that boxes with rewards at the beginning were strongly preferred and overvalued. Object-value associative memory was impaired in boxes with early rewards, suggesting that value information was linked to the box rather than the objects. However, when tested after an overnight delay, participants equally preferred boxes with any cluster of reward, whether at the beginning, middle, or end of the experience. Finally, we demonstrated that evaluating shortly after an experience led to lasting preferences for early rewards. Overall, we show that people summarize rewarding experiences in a non-linear and time-dependent way, unifying prior work on affect, memory, and decision-making. We propose that short-term preferences are biased by first impressions. However, when we wait and evaluate an experience after a delay, we summarize rewarding events in memory to inform adaptive longer-term preferences. Preferences depend on when rewards occur and when we first evaluate an experience.