Four experiments and one study were conducted to test the hypothesis that stimuli associated with spending can elicit spending responses. In all experiments, credit card stimuli were either present or absent in situations in which subjects were given an opportunity to spend. Credit card stimuli directed spending such that the probability, speed, or magnitude of spending was enhanced in the presence of credit card cues. A conditioning explanation was used to interpret the results.
Feinberg, R. A. (1986). Credit cards as spending facilitating stimuli: A conditioning interpretation. Journal of consumer research, 13(3), 348-356.