A rumbling stomach can put even the most disciplined shopper off their stride—but there's another culprit. As it turns out, drinking coffee beforehand can turn us into impulsive buyers as well. A study published in the Journal of Marketing reveals that consumers tend to spend more after drinking caffeinated beverages such as coffee or coke. The reason is simple: Caffeine suppresses sleep-related hormones, boosts alertness, and ultimately encourages more spontaneous, less restrained behavior.
Coffee makes us impulsive
To test this theory, Dipayan Biswas and his research team at the University of Florida conducted an experiment outside several retail stores in different countries. About 300 shoppers were handed one of three beverages before entering the store—regular coffee with 100 milligrams of caffeine, a decaf version, or water—all free of charge.
Once the shoppers were done shopping, their receipts displayed a clear pattern: Those, who had consumed caffeinated coffee, made more impulse purchases and spent noticeably more money. Subsequent tests in multiple countries produced the same outcome, confirming that caffeine consistently heightens both energy levels and impulsive buying tendencies.
Sweets, snacks and home decor
To better understand how caffeine affects not just spending but decision-making, the researchers examined the types of products that had been purchased. Participants who drank caffeinated coffee were more likely to reach for things like sweets, special snacks or decorative items. Those who had drunk decaf coffee, however, gravitated towards practical, everyday goods.
The takeaway? A pre-shopping cup of coffee doesn’t just make us more spontaneous—it nudges us toward pleasure-driven choices.
