Kalpesh Desai, associate professor of marketing in the School of Management, and his colleagues (Manoj Thomas, assistant professor of marketing at Cornell University and Satheesh kumar Seenivasan, doctoral candidate in marketing at the University at Buffalo) examined the actual purchases made by 1,000 households at a grocery store during a six-month period. They found that participants who paid for groceries with a credit or debit card showed a greater tendency to buy unhealthy foods that are impulsive.

Furthermore, the researchers found that paying with cash decreased impulsive-unhealthy purchases. Findings from several experiments revealed that cash payments are psychologically more painful than card payments, and this pain of payment can curb the impulsive responses to buy unhealthy food items.

The findings suggest that internal psychological states and modes of payment interactively influence what types of foods are purchased. Given that many consumers struggle so mightily to make healthy choices, understanding that using plastic increases their vice purchases may help people control impulsive behavior.