How caffeine can drain your wallet: The hidden cost of pre‑shopping coffee

If you want to avoid impulsive reactions to "sale" signs and limit your spending during a shopping centre visit, skip the coffee. University of South Florida scientists have demonstrated that caffeine influences shopping behaviour.

An experiment conducted by the research team in three different retail stores revealed that customers who drank a free cup of caffeinated coffee before entering the store spent, on average, 50% more money and bought 30% more items than those who drank decaffeinated coffee or water. The results of these studies were published in the "Journal of Marketing."

"Caffeine, as a powerful stimulant, releases dopamine in the brain, which excites the mind and the body. This leads to a higher energetic state, which in turn enhances impulsivity and decreases self-control," said Dipayan Biswas from the University of South Florida, a member of the research team.

As part of the experiment, coffee machines were placed at the entrances of a mall, a home goods store in France, and a department store in Spain. Each of over 300 customers, upon entering the store, received a free cup of coffee. Half of them chose coffee containing about 100 milligrams of caffeine, while the rest opted for decaffeinated coffee or water. Customers presented their receipts to the researchers after completing their shopping. It was found that those who consumed caffeinated coffee spent more money and bought more items than those who drank non-caffeinated beverages.

Researchers also observed that caffeine affects the types of products purchased. Those who drank caffeinated coffee more often chose unnecessary items, such as scented candles.

A similar experiment was conducted under laboratory conditions, focusing on online shopping. 200 business school students were divided into groups: one drinking decaffeinated coffee and the other caffeinated coffee. They were asked to choose items from a list containing 66 options. Those consuming caffeine more often chose impulse-buy items, like a massager, while the others preferred practical items, such as a notebook.

"While moderate amounts of caffeine intake can have positive health benefits, there can be unintended consequences of being caffeinated while shopping. That is, consumers trying to control impulsive spending should avoid consuming caffeinated beverages before shopping," emphasised Dipayan Biswas.

According to researchers, understanding how caffeine affects our spending is essential. Coffee is one of the most potent stimulants that remains legal and widely available.

American scientists also suggest that store owners wanting to maximise profits might consider the influence of caffeine on customers' moods in their marketing strategies.