Cash is healthier? Credit and debit increase impulsive food purchases

"Two factors contribute to this intriguing effect," write authors Manoj Thomas (Cornell University), Kalpesh Kaushik Desai (State University of New York, Binghamton), and Satheeshkumar Seenivasan (State University of New York, Buffalo). "First, there is a correlation between unhealthiness and impulsiveness of food items: Unhealthy food items also tend to elicit impulsive responses. Second, 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 authors conducted an analysis of actual shopping behavior of 1,000 households over a period of six months. They found that shopping carts had a larger proportion of food items rated as impulsive and unhealthy when shoppers used credit or debit cards versus cash. In follow-up studies they found that the vice-regulation effect of cash payment is due to the "pain" of paying in cash, and that the effect is stronger in consumers who are chronically more sensitive to the pain of payment.

"The notion that mode of payment can curb impulsive purchase of unhealthy food products is substantially important," the authors write. "The epidemic increase in obesity suggests that regulating impulsive purchases and consumption of unhealthy food products is a steep challenge for many consumers." 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.

The authors suggest that there may be a connection between rising obesity and changing modes of payment. According to the Centers for Disease Control, 34 percent of U.S. adults are obese. And nearly 40 percent of all purchases in 2006 were paid by credit and debit cards. "The relationship between these trends suggests that self-control is not entirely volitional; it can be facilitated or impeded by seemingly unrelated contextual factors that influence people's visceral feelings."