Institute for Money, Technology & Financial Inclusion

Imagine that someone approached you and asked how much you would be willing to pay for a bar of soap or a bag of potato chips? It seems like a simple question.

You would probably, though, ask which bar of soap and which potato chips? Think a bit longer, and you might be asking “pay for them how?”

Researchers have found that the last question – about the form of payment -- matters. For example, paying by credit card rather than cash changes how consumers spend: Studies suggest that using plastic induces consumers to pay higher tips at restaurants, buy more junk food, and pay more for a chance to see a pro basketball game. These results are not always robust, and studies struggle to separate the liquidity effect of credit cards from the psychological effect of using plastic vs. cold, hard cash. Still, the weight of the evidence suggests that people spend more when using credit cards (or even when thinking about credit cards) for reasons that are at least partly psychological.