Small gifts and tips increase tipping

This study analysed 6,700 websites in an unprecedented A/B test. 

The results proved something that Dr Robert Cialdini had been preaching for years. 

Today, on Nudge, Robert Cialdini joins me again, covering another of his seven principles of persuasion. 

And I share a marketing lesson that (I think) every business needs to know.

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Today’s sources: 

Bell, T. [Taylor Bell]. (2025, February 13). Inside Trader Joe’s: The genius strategy behind its cult following (and low prices) [Video]. YouTube.

Bornstein, R. F., Leone, D. R., & Galley, D. J. (1987). The generalizability of subliminal mere exposure effects: Influence of stimuli perceived without awareness on social behavior. Journal of Personality and Social Psychology, 53(6), 1070–1079.

Browne, D., & Swarbrick-Jones, A. (2017). The science of persuasion in e-commerce: An analysis of 6,700 online A/B tests. Conversion Rate Experts.

Danziger, S., Levav, J., & Avnaim-Pesso, L. (2011). Extraneous factors in judicial decisions. Proceedings of the National Academy of Sciences of the United States of America, 108(17), 6889–6892.

Drachman, D., deCarufel, A., & Insko, C. A. (1978). The extra credit effect in interpersonal attraction. Journal of Experimental Social Psychology, 14(5), 458–465.

Fang, X., Singh, S. N., & Ahluwalia, R. (2007). An examination of different explanations for the mere exposure effect. Journal of Consumer Research, 34(1), 97–103.

Gladka, A., & Żemła, M. (2016). Effectiveness of reciprocal rule in tourism: Evidence from a city tourist restaurant. European Journal of Service Management, 17(1), 57–63.

Mita, T. H., Dermer, M., & Knight, J. (1977). Reversed facial images and the mere-exposure hypothesis. Journal of Personality and Social Psychology, 35(8), 597–601.

Nicholson, C. Y., Compeau, L. D., & Sethi, R. (2001). The role of interpersonal liking in building trust in long-term channel relationships. Journal of the Academy of Marketing Science, 29(1), 3–15.

Razran, G. (1940). Conditioned response changes in rating and appraisal. Psychological Bulletin, 37(6), 481–493.

Shotton, R. (2023). The illusion of choice: 16½ psychological biases that influence what we buy. Harriman House.

Strohmetz, D. B., Rind, B., Fisher, R., & Lynn, M. (2002). Sweetening the till: The use of candy to increase restaurant tipping. Journal of Applied Social Psychology, 32(2), 300–309.

Zajonc, R. B., & Rajecki, D. W. (1969). Exposure and affect: A field experiment. Psychonomic Science, 17(4), 216–217.