Do Purchases Work as Self-Signalling
People read their own actions as evidence about who they are, and some shade those actions to get good news. Whether an ordinary purchase does that work is a narrower question. The experiments come from cold-water tests and charity, a leading book on hidden motives says private motives lead nowhere without an audience, and cost decides how far the message counts.
Answer to the question
Do we buy things to prove something to ourselves?
Partly, though the evidence comes from nearby behaviour, not shopping. Students shaded a cold-water test toward good news about their health in 1984, and costly good deeds were followed by more consistent behaviour than costless ones in 2012. A leading book on hidden motives holds that private motives lead nowhere without an audience.
Key takeaways
- Quattrone and Tversky (1984) told students that a pattern of cold-water tolerance after exercise signalled a long, healthy life or a shorter one. On the second trial their tolerance moved toward the good-news pattern.
- Prelec and Bodner (2003) model choices as carrying diagnostic utility, the lift or dent to self-image from what an act reveals. Buying an expensive item on credit is on their list of examples, in a paper with no new experiments.
- Simler and Hanson (2018) argue that incentives beginning and ending inside one's head lead nowhere (p. 295). The rule is stated in the book and not tested.
- Gneezy and colleagues (2012) found in a laboratory and a field experiment that costly good deeds signalled identity and were followed by consistent behaviour, while costless ones signalled less.
Incentives that begin and end inside one's head, Kevin Simler and Robin Hanson write in The Elephant in the Brain, "ultimately lead nowhere". If so, self-signalling, choosing an act partly for what it tells you about yourself, is a performance for onlookers or nothing at all.
The standard laboratory case points the other way. In 1984 George Quattrone and Amos Tversky asked students to hold an arm in cold water until it hurt too much to continue. The students then exercised and repeated the test, having been told that a long, healthy life went with higher tolerance after exercise in one group and with lower tolerance in the other. On the second trial their tolerance moved toward the good-news pattern.
Economists later gave that result a model, and the book gave it an objection. This piece follows the idea from its older name to the model, sets the objection beside it, and asks what the cost of an act adds. Whether an ordinary purchase does the same work is a narrower question than any of the studies asked.
Self-perception becomes a model
Daryl Bem's self-perception theory (1972) is the older name. People work out what they believe and prefer partly by watching what they do, much as an outside observer would, and they do it most readily when their internal cues are weak or ambiguous. Self-signalling is the later name, and it comes from behavioural economics. The difference is one of direction. Bem's observer reads behaviour that has already happened. Self-signalling has the person choose the behaviour partly for the reading it will produce.
Drazen Prelec and Ronit Bodner gave self-signalling its formal version in 2003. A choice, on their account, carries two kinds of reward. Outcome utility comes from what the action directly produces. Diagnostic utility is the lift or the dent to self-image from what the action reveals about the person. Their list of everyday cases includes giving to charity, drinking before noon, jogging in a heat wave, voting, and buying an expensive item on credit.
The last of these is the purchase the title asks about. It appears as an illustration in a theoretical paper that reports no new experiments of its own and leans on the cold-water study and a handful of others for support. One of them is Bodner's own earlier work on contingent pledges, as the paper describes it. People who saw themselves as insufficiently altruistic pledged more when the chance of having to pay was low.
The 1984 paper ran a second experiment, on voting. In it, 315 undergraduates read one of two theories of who decides an election's margin. Only one let them believe their own vote showed what like-minded people would do, and more of them said they would vote under it, although a single vote caused exactly the same thing under both. Prelec and Bodner call that kind of motive magical, a belief that one's action signals how others will behave. It is self-signalling stretched to its limit, and it shows the habit running ahead of the logic.
Why the book disagrees
The Elephant in the Brain (Kevin Simler and Robin Hanson, 2018) is the seed text here, and its fifth chapter takes the opposite side. A belief held privately changes nothing for anyone else, so a motive that begins and ends inside one's own head cannot drive behaviour. The authors illustrate it with a game of chicken, in which a driver who removes the steering wheel gains only because the other driver believes it cannot be steered (pp. 77 to 79). They quote the line that "ignorance is at its most useful when it is most public" (p. 79), and they state the general rule at p. 295: incentives that begin and end inside one's head "ultimately lead nowhere".
Taken straight, the rule turns self-signalling into an audience effect in disguise, or into nothing. A shopper who buys running shoes to become a runner has, on this reading, been working for whoever might notice. The same chapter supplies an answer to the cold-water students too. Its thesis is that people hide motives from themselves the better to hide them from others (pp. 74 and 80), which makes the students' failure to notice their own shading an exhibit for the book, not against it.
The book offers no test of the rule. A buyer who enjoys the purchase and a buyer who wants credit for it both confirm the model, and nothing in the argument says what result would count against it. That is the pattern we call the unfalsifiable frame. Bem's mechanism, in its own formulation, does not require an audience at all.
A buyer who enjoys the purchase and a buyer who wants credit for it both confirm the model.
Cost sets the signal
The best evidence on the private reading sits in a different part of the literature. Ayelet Gneezy and four colleagues reported in Management Science in 2012 that the cost of a good deed shapes what follows it. A costly prosocial act signals a prosocial identity, and people then keep behaving in line with that self-image. A costless act signals little, so later behaviour is less consistent and may even decline, a pattern the authors tie to moral licensing. A laboratory experiment and a large field experiment both supported the account.
The tested behaviour is prosocial, not shopping, and the published abstract does not separate choices that were observed from choices that were not. The result still bears on purchases, by way of its cost mechanism. Price is the plainest cost a buyer pays, and the logic that makes a costly signal believable to an onlooker is the same logic this account applies to the person who paid. Two earlier pieces here follow that logic outward, to other people, in luxury labels and in visible green purchases.
Bem's mechanism has a mixed record in a consumer-adjacent setting that has been tested hard. A 1975 field experiment put the self-perception explanation of the foot-in-the-door effect to a direct test. About 52 per cent agreed to a moderate request after a small yes, against about 33 per cent of a control group and about 22 per cent after a large request they were almost sure to refuse. A 1983 meta-analysis then judged it too imprecise to make clear predictions, and a 1984 meta-analysis called it seriously flawed as an account of the effect.
| Account | Basis | Claim | Tested on |
|---|---|---|---|
| Bem, 1972 | Theory of self-perception | Behaviour is read as evidence, most when inner cues are weak | Foot-in-the-door studies, with a mixed record |
| Quattrone and Tversky, 1984 | Cold-water and voting experiments | People shade behaviour toward good news | Students, one laboratory task each |
| Prelec and Bodner, 2003 | Formal model | Choices carry diagnostic utility beyond their outcomes | No new experiments |
| Simler and Hanson, 2018 | Book argument | Private motives lead nowhere without a witness | Not tested |
| Gneezy and colleagues, 2012 | Laboratory and field experiments | Costly good deeds signal identity and are followed by consistent behaviour | Prosocial acts, not shopping |
When purchases become evidence
Two claims about self-signalling hold across these accounts. People read their own actions as evidence about themselves, and they shade those actions when the reading matters to them. The size of the signal depends on what the act cost.
Whether a retail purchase alone does the self-signalling is not established, and neither is the book's claim that the work is always done for an audience. On that evidence, a costly purchase that is followed through is the kind most likely to behave like proof, and a cheap one risks behaving like a licence. That is inferred from the cost mechanism, because no study cited here tested a till or compared a costly purchase with a cheap one.
Common questions
Do we buy things to prove something to ourselves?
Partly, though the evidence comes from nearby behaviour, not shopping. Students shaded a cold-water test toward good news about their health (1984), and costly good deeds were followed by more consistent behaviour than costless ones (2012). A leading book on hidden motives holds that private motives lead nowhere without an audience.
What is self-signalling?
Self-signalling is choosing an action partly for what it will tell you about yourself. Prelec and Bodner call the reward diagnostic utility, the gain or loss in self-image from what a choice reveals, as distinct from the outcome the choice produces.
How is self-signalling different from self-perception theory?
Bem's self-perception theory describes people reading behaviour that has already happened. Self-signalling adds a choice: the person picks the behaviour partly for the reading it will give.
Is self-signalling really about other people?
The Elephant in the Brain argues that it is, because private motives have no effect on anyone. The book offers no test of that rule, and Bem's own mechanism does not need an audience.
Sources
Bem, D. J. (1972). 'Self-perception theory.' In L. Berkowitz (Ed.), Advances in Experimental Social Psychology, Vol. 6, pp. 1-62. Academic Press.
Quattrone, G. A., & Tversky, A. (1984). “Causal versus diagnostic contingencies: On self-deception and on the voter’s illusion.” Journal of Personality and Social Psychology, 46(2), 237-248. doi:10.1037/0022-3514.46.2.237.
Prelec, D., & Bodner, R. (2003). 'Self-signaling and diagnostic utility in everyday decision making.' In I. Brocas & J. D. Carrillo (Eds.), The Psychology of Economic Decisions, Vol. 1. CEPR Press, 2003. https://cepr.org/chapters/self-signaling-and-diagnostic-utility-everyday-decision-making
Simler, K., & Hanson, R. (2018). The Elephant in the Brain: Hidden Motives in Everyday Life. Oxford University Press. Ch. 5, pp. 73-89, 295.
Gneezy, A., Imas, A., Brown, A., Nelson, L. D., & Norton, M. I. (2012). 'Paying to be nice: Consistency and costly prosocial behavior.' Management Science, 58(1), 179-187. doi:10.1287/mnsc.1110.1437.
Snyder, M., & Cunningham, M. R. (1975). 'To comply or not comply: Testing the self-perception explanation of the foot-in-the-door phenomenon.' Journal of Personality and Social Psychology, 31(1), 64-67. doi:10.1037/h0076245.
Beaman, A. L., Cole, C. M., Preston, M., Klentz, B., & Steblay, N. M. (1983). 'Fifteen years of foot-in-the-door research: A meta-analysis.' Personality and Social Psychology Bulletin, 9(2), 181-196. doi:10.1177/0146167283092002.
Dillard, J. P., Hunter, J. E., & Burgoon, M. (1984). 'Sequential-request persuasive strategies: Meta-analysis of foot-in-the-door and door-in-the-face.' Human Communication Research, 10(4), 461-488.