Order matters : the effect of sequential presentation on economic decision making.

Summary Standard decision theories assume that choices are based on instantaneous value readings from stable utility functions. Therefore, decision outcomes should be independent of how information is acquired. However, the information related to a choice is often encountered in a sequential manner. In this thesis, we have attempted to characterize the influence of sequential presentations on economic decision making. In our first study, we used a multiple choice task involving a sequential presentation of different options. We showed that the order of presentation could influence the direction of value comparison: subjects were more likely to choose the best option when it was presented at the beginning of a trial. We hypothesize that this is due to an active but implicit pairwise comparison process during the sequential sampling process. We validated this model formally via a Bayesian model comparison. In the second study, we compared the simultaneous presentation of information about two two-attribute options with various sequential presentations. We found that early information about a first option or attribute can modulate the weight given to later information and explain variations in response time. Overall, we have shown that the order of presentation influences choice, inviting a revision of standard decision theory.