Consumers choose first and develop preferences later, reports a paper published online this week in Nature Human Behaviour that analyses individual purchase data from one of the world’s largest retailers. The study shows that people systematically explore new products while shopping, but the longer they stick with one brand, the less likely they are to explore other brands or use coupons intended to foster new product exploration.

Humans are routinely faced with the decision to exploit prior choices or explore new options. Previous research has suggested that, over time, as the value of a past choice becomes less certain, the probability of such exploration should increase.

Here, Peter Riefer and colleagues show that this is not always the case in the real world. They analysed purchases made in six product categories over several years by more than 280,000 anonymous supermarket customers, and found people explored new brands 40% of the time. However, new product exploration declined with longer purchase streaks and coupons reinforced purchase behaviour, rather than encouraging consumers to explore new options. The authors suggest that customers may think they are buying what they like, but in fact are adjusting what they like to fit what they are buying. Shopper behaviour is widely studied and the use of individual-level big data like the kind used in this research offers new opportunities to advance our knowledge of human decision-making in many venues.

Although the research shows previous purchases are a strong determinant of future preferences, consumers do explore with some predictability. These periods of exploration represent an opportunity for promoting alternative, and perhaps healthier choices.