Coherency Maximizing Exploration in the Supermarket 1

In uncertain environments, effective decision makers balance exploiting options that are 8 currently preferred against exploring alternative options that may prove superior 1,2. For 9 example, a honeybee foraging for nectar must decide whether to continue exploiting the 10 current patch or move to a new location 3-6. When the relative reward of options changes over 11 time, humans explore in a normatively correct fashion, exploring more often when they are 12 uncertain about the relative value of competing options 7-11. However, rewards in these 13 laboratory studies were objective (e.g., monetary payoff), whereas many real-world decision 14 environments involve subjective evaluations of reward (e.g., satisfaction with food choice). 15 In such cases, rather than choices following preferences, preferences may follow choices with 16 subjective reward (i.e., value) to maximize coherency between preferences and behaviour 17 12,13. If so, increasing coherency would lessen the tendency to explore while uncertainty 18 increases, contrary to previous findings. To evaluate this possibility, we examined the 19 exploratory choices of more than 280,000 anonymized individuals in supermarkets over 20 several years. Consumers' patterns of exploratory choice ran counter to normative models for 21 objective rewards 7-9,14 – the longer the exploitation streak for a product, the less likely were 22 people to explore an alternative. Furthermore, customers preferred coupons to explore 23 alternative products when they have recently started an exploitation streak. These findings 24 suggest interventions to promote healthy lifestyle choices. 25 26 Effective decision making requires balancing exploratory and exploitative behaviour 1,2,15. 27 For example, finding a restaurant that bests one's current favourite requires some exploration. 28 The timing of exploration is also critical. Normatively, the rate of exploration should increase 29 as uncertainty about the relative goodness of options increases 8. For example, one may give 30 a restaurant a second chance after a year has passed because the service could have improved 31 in the interim. People in laboratory studies with objective rewards (e.g., money) behave in a 32 manner consistent with the ideal actor 7-9,14 , exploring more often when uncertainty is high. 33 This efficient, systematic exploration appears to demand capacity-limited cognitive resources 34 9 and rely on frontal dopamine brain circuitry 14,15. However, as in the restaurant example, 35 rewards can be subjective rather than objective. Although it's clear that higher monetary 36 rewards are better, comparing the reward associated with two dining experiences is more 37 …