Does a warm drink make us kinder?
The 2008 warm-cup finding, the larger tests that did not find it, and where we land.
Answer to the question
Does a warm drink make us kinder?
Not on the evidence so far. Lawrence Williams and John Bargh reported in 2008 that holding a hot drink or pad shifted judgments and gift choices, but larger double-blind repeats found near-zero effects, and three independent labs found none across 861 participants. A warm drink is still pleasant to share.
Key takeaways
- In 2008 Lawrence Williams and John Bargh reported that people holding hot coffee judged a described stranger as warmer in personality, and that people holding a hot pad were more likely to pick a gift for a friend.
- Hans IJzerman and Günn Semin reported in three experiments that warmer conditions raised perceived social closeness, a separate outcome from kindness.
- Christopher Chabris and colleagues repeated both original experiments with 128 and 177 participants and double-blind procedures, and found near-zero effects.
- Three independent labs led by Dermot Lynott repeated the gift-choice experiment and found no effect in any lab or across 861 participants.
- We side with the larger tests: the evidence does not show that a warm drink makes the person holding it kinder.
A warm drink held for a moment, then a rating of a stranger: that was the whole procedure of a famous experiment, and it leaves a plain question for anyone who has handed a friend a hot coffee. Does a warm drink make us kinder? The idea is easy to believe, because warmth in the hand and warmth toward a person share a word in everyday speech, and a quick, cheap test appeared to bear it out. The larger tests that followed give an answer.
Does a Warm Drink Change How We Judge Others?
In the first experiment, people who briefly held a cup of hot coffee judged a described stranger as having a warmer personality, more generous and caring, than people who held iced coffee. In the second, people holding a hot therapeutic pad were more likely to choose a gift for a friend instead of themselves than people holding a cold pad. Lawrence Williams and John Bargh, who ran the work, started from research pointing to the insula, a brain region involved in processing both physical temperature and trust, and proposed that a warm experience could raise interpersonal warmth without the person noticing.
The idea had company. Hans IJzerman and Günn Semin reported three experiments in Psychological Science in which warmer conditions, created with warm beverages or comfortably warm rooms, raised perceived social closeness, produced more concrete language and shifted attention toward relationships. Their account was that the vocabulary of everyday life, warm welcomes and cold shoulders, tracks something real about how the body and social life connect, which is the idea behind Embodied Cognition more widely.
Read carefully, the two lines of work on the warm drink ask different questions. The second Williams and Bargh experiment comes closest to kindness, since it offers a choice between treating a friend and treating oneself. The first measures a judgment about someone else, and the closeness experiments measure how near people feel and how they talk. A warm drink making a stranger seem pleasant is a smaller claim than a warm drink making the person who holds it generous, and the title question asks for the larger one. Evidence for the smaller claim would not settle the larger one.
What Did Larger Tests Find, and Where Do We Stand?
Christopher Chabris and colleagues repeated both Williams and Bargh experiments, the coffee cup and the therapeutic pad, in field settings. They used more than three times the original number of participants, with 128 in one and 177 in the other, and double-blind procedures, in which neither the participant nor the person running the session knew which temperature had been assigned. The effects were close to zero in both. Bayesian analyses showed substantially more support for no effect than for the original warmth hypothesis. The paper appeared in Social Psychology, and it set these samples beside the original ones of 41 and 53 people.
We side with the larger tests on the claim as the title states it. The original report was a first look with small groups, and a first look is how a question gets asked; the later teams asked it again with the original design and many more people, and the answer about the warm drink came back flat. Expectation is a different route from the one Williams and Bargh proposed, since it works through what people anticipate and then report, as When Expecting Side Effects Causes Them shows in a separate setting. The warm drink in these experiments was meant to act without the person noticing, and the larger tests give no sign that it did.
Two things stay open and we leave them open. First, the closeness experiments address a different outcome, how near people feel and how they describe relationships, and they stand as their own question. Second, a warm drink can still be a pleasant thing to share with a friend, but the evidence does not say that the warmth of the drink makes the person holding it more generous. How sample size shapes what a first study can show is the subject of What Forty-One Participants Buys, and the warm cup experiments are one case of it.
What Did Repeats and Three Independent Labs Report?
Daniel Kahneman's Thinking, Fast and Slow gave priming a chapter of its own and carried studies of this kind to a very wide readership, which is part of why repeating them mattered beyond the lab. The warm drink and warm pad experiments were repeated with features that make a second test informative.
- Samples larger than the original, in the Chabris tests more than three times larger.
- Double-blind procedures, so that the person running each session did not know the condition.
- Several independent labs running the same task, as in the tests described below.
- Analysis able to say whether the data favour no effect, not only whether an effect was missed.
Social Priming and The Replication Crisis describes how a claim stated clearly enough can be tested, and then is. The most specific result came from Dermot Lynott and colleagues, published in Social Psychology in 2014. They ran three high-powered, independent replications of the second Williams and Bargh experiment, the one closest to kindness. Participants evaluated a hot or cold instant therapeutic pack and then chose a reward for taking part, framed either as a treat for a friend or as a reward for themselves. Williams and Bargh predicted that the hot pack would raise the chance of the friend choice.
A design of this kind gives the original idea every chance to show itself: the same task, the same choice, a hot pack against a cold one, and several labs working separately so that no single room, experimenter or sample could carry the result. The authors concluded that there was no evidence that brief exposure to a warm pack leads to more prosocial responding than a cold one, and the effect did not appear in any single lab, nor when the three sets of results were pooled across 861 participants in total.
Common questions
Does a warm drink make us kinder?
The research does not show it. Williams and Bargh reported that holding a hot coffee or hot pad shifted judgments and gift choices in 2008, but larger double-blind repeats found near-zero effects, and three independent labs found no effect across 861 participants.
What did the original warm cup study find?
People who briefly held hot coffee rated a described stranger as warmer in personality than people who held iced coffee, and people holding a hot pad were more likely to choose a gift for a friend instead of themselves.
Why did later studies use bigger samples?
The original experiments had 41 and 53 participants. Chabris and colleagues used 128 and 177 participants with double-blind procedures, and Lynott and colleagues pooled 861 across three labs.
Do warm rooms or drinks change how close we feel?
IJzerman and Semin reported in three experiments that warmer conditions raised perceived social closeness and concrete language. That is a separate outcome from kindness, and it is judged on its own evidence.
Sources
Kahneman, D. Thinking, Fast and Slow. Seed book; vault hub Books/Thinking Fast and Slow.
Williams, L. E., & Bargh, J. A. (2008). “Experiencing physical warmth promotes interpersonal warmth.” Science, 322(5901), 606-607. doi:10.1126/science.1162548 https://doi.org/10.1126/science.1162548
IJzerman, H., & Semin, G. R. (2009). “The thermometer of social relations: Mapping social proximity on temperature.” Psychological Science, 20(10), 1214-1220. doi:10.1111/j.1467-9280.2009.02434.x https://doi.org/10.1111/j.1467-9280.2009.02434.x
Chabris, C. F., Heck, P. R., Mandart, J., Benjamin, D. J., & Simons, D. J. (2019). “No evidence that experiencing physical warmth promotes interpersonal warmth.” Social Psychology, 50(2), 127-132. doi:10.1027/1864-9335/a000361 https://doi.org/10.1027/1864-9335/a000361
Lynott, D., Corker, K. S., Wortman, J., Connell, L., Donnellan, M. B., Lucas, R. E., & O'Brien, K. (2014). “Replication of Experiencing physical warmth promotes interpersonal warmth by Williams and Bargh (2008).” Social Psychology, 45(3), 216-222. doi:10.1027/1864-9335/a000187 https://doi.org/10.1027/1864-9335/a000187