PT - JOURNAL ARTICLE AU - Aaron M. Bornstein AU - Mel W. Khaw AU - Daphna Shohamy AU - Nathaniel D. Daw TI - What’s past is present: Reminders of past choices bias decisions for reward in humans AID - 10.1101/033910 DP - 2015 Jan 01 TA - bioRxiv PG - 033910 4099 - http://biorxiv.org/content/early/2015/12/08/033910.short 4100 - http://biorxiv.org/content/early/2015/12/08/033910.full AB - We provide evidence that decisions are made by consulting memories for individual past experiences, and that this process can be biased in favor of past choices using incidental reminders. First, in a standard rewarded choice task, we show that a model that estimates value at decision-time using individual samples of past outcomes fits choices and decision-related neural activity better than a canonical incremental learning model. In a second experiment, we bias this sampling process by incidentally reminding participants of individual past decisions. The next decision after a reminder shows a strong influence of the action taken and value received on the reminded trial. These results provide new empirical support for a decision architecture that relies on samples of individual past choice episodes rather than incrementally averaged rewards in evaluating options, and has suggestive implications for the underlying cognitive and neural mechanisms.