Rebate or Bait? A Model of Regret and Time Inconsistency in Consumer Behaviour

In this paper we develop a theory of time-inconsistency and regret that is motivated by evidence on a 'price discrimination' technique widespread in the United States, namely mail-in-rebate promotions. Our model combines partial naivete about future self-control problems and the sunk-cost effect (regret). We assume that agents deviating from their past choices suffer a certain emotional disutility from having brought a bad decision in the past and that this emotional disutility is negatively related to the length of the period between the choice made and the deviation from it. In the context of our application the model explains why in a multi period setting a large number of consumers respond to the rebate offers intending to redeem the rebate and then fail to provide the necessary effort when it comes to collect their money. Moreover, consumer failure to accomplish a task planned in the past (e.g. redeeming the rebate) is more likely when the deadline of completion is longer. This prediction is supported by experimental studies on various forms of procrastination and by field and experimental evidence on mail-in-rebates. We review a number of areas for which the theory may have important implications.