Option similarity modulates the link between choice and memory.

Choices made in everyday life are highly variable. Sometimes, you may find yourself choosing between two similar options (e.g., breakfast foods to eat) and other times between two dissimilar options (e.g., what to buy with a gift certificate). The goal of the present study was to understand how the similarity of choice options affects our ability to remember what we choose and what we did not choose. We hypothesized that choosing between similar as compared to dissimilar options would evoke a comparison-based strategy (evaluating options with respect to one another), fostering a relational form of encoding and leading to better memory for both the chosen and unchosen options. In Experiment 1, participants reported their strategy when choosing between pairs of similar or dissimilar options, revealing that participants were more likely to use a comparison-based strategy when faced with similar options. In Experiment 2, we tested memory after participants made choices between similar or dissimilar options, finding improved memory for both chosen and unchosen options from the similar compared to dissimilar choice trials. In Experiment 3, we examined strategy use when choosing between pairs of similar or dissimilar options and memory for these options. Replicating and extending the results of the first two experiments, we found that participants were more likely to use a comparison-based strategy when choosing between similar than dissimilar options, and that the positive effect of similarity on memory was stronger for unchosen than chosen options when controlling for strategy use. We interpret our results as evidence that option similarity impacts the mnemonic processes used during choice, altering what we encode and ultimately remember about our choices.