Is Self-Deception a Persuasion Tool
Trivers proposed that we deceive ourselves the better to deceive others. Two experiments find that expecting to persuade raises confidence. What they leave open is whether evolution built the habit, or whether motivated bias or self-signalling does the work.
Answer to the question
Is self-deception a persuasion tool?
In two experiments with 688 participants combined, people who expected to earn money by persuading a partner were more overconfident about their own performance, and the added confidence made them more persuasive. That supports an incentive effect. It does not show that evolution built self-deception for the purpose.
Key takeaways
- Trivers argued that self-deception evolved to make deceiving others more effective: it hides the cues a conscious liar leaks, lowers cognitive load and limits retribution if the lie is found out. The 2011 article that sets this out was written with William von Hippel.
- Schwardmann and van der Weele (2019) ran two experiments with 688 participants combined. Those told they could earn money by convincing a partner that they had done better were significantly more overconfident in private than a control group.
- In the same study, a noisy feedback signal that raised confidence made participants more persuasive in later interactions.
- Soldà, Ke, Page and von Hippel (2020) found that people who expected to persuade overestimated their performance more and steered their information search toward positive feedback. The evidence that confidence made them more persuasive is described as suggestive.
- Mele (2001) argues that motivation can bias how people assess evidence with no intention to mislead the self, and McKay and colleagues (2011) offer a self-signalling alternative. Simler and Hanson's own preferred mechanism, self-discretion, cites no study.
"We deceive ourselves the better to deceive others."
Robert Trivers's line is quoted twice in Chapter 5 of Kevin Simler and Robin Hanson's The Elephant in the Brain (pp. 74, 80), and it carries the book's whole account of why people hide their motives from themselves. As a claim about what self-deception is for, it has been tested in the laboratory since 2019. Two experiments found that people who expected to persuade became more confident in their own performance. They did not show that evolution built the habit, or that no simpler process explains it.
What the Theory Predicts and Two Experiments Testing It
Robert Trivers argued that self-deception evolved to make deceiving other people more effective. A person who believes the story leaks fewer of the cues that give a conscious liar away, carries a lighter cognitive load, and faces less retribution if the lie is found out. William von Hippel set the argument out with him in a 2011 article in Behavioral and Brain Sciences. Self-enhancement, in that account, lets people look more confident than the evidence warrants, which brings social advantages.
Simler and Hanson give the argument for self-deception a picture. Erasing a mountain range from your map brings relief, but the enemy still surrounds you, and a general who indulged the fancy would lose to one who did not (pp. 76 to 77). If comfort were the aim, the authors say, a brain could simply be built to feel less anxious. Distorting the map is a "sloppy hack" (p. 76), and the book's answer to why a brain would do it anyway is an audience.
That reading makes a prediction. If self-deception serves persuasion, people who expect to need persuading should hold more inflated beliefs about themselves than people who do not.
Peter Schwardmann and Joël van der Weele tested the prediction in two experiments, with 688 participants combined, reported in Nature Human Behaviour in 2019 (volume 3, pages 1055 to 1061). After a difficult task, half of the participants were told they could earn money by convincing a partner, in a brief face-to-face exchange, that they had performed better. Their private beliefs were significantly more overconfident than those of the control group.
"overconfidence arises as a strategy to influence others in social interactions." Soldà, Ke, Page and von Hippel (2020)
The authors then used a noisy feedback signal to raise some participants' confidence, and in later interactions the boost made those participants more persuasive.
Alice Soldà and colleagues, von Hippel among them, ran a related design, published in Experimental Economics in 2020 (volume 23, pages 604 to 631). Participants were paid either for forming accurate beliefs about their test performance or for convincing others that they had performed well, and the researchers varied how much they could learn about their own results. Those who expected to persuade overestimated their performance more, and, given the chance, steered their information search toward more positive feedback. The authors report suggestive evidence that the higher confidence made participants more persuasive. They write that "overconfidence arises as a strategy to influence others in social interactions."
Von Hippel co-wrote the 2011 theory and the second test.
The first test came from a separate pair of authors, at the University of Munich and the University of Amsterdam.
Could Motivated Bias Explain the Same Result Without a Plan?
The experiments show that an incentive to persuade moves reported confidence upward. A rival account of self-deception predicts the same movement. In Self-Deception Unmasked (Princeton University Press, 2001), the philosopher Alfred Mele argues that it is a mistake to treat self-deception as a trick that one part of the mind plays on another with intent. His account rests on everyday reasoning research instead: emotion and motivation can bias how a person assesses the evidence for a belief, without the person knowing.
On that reading, a participant who wants the persuasion payment attends more to good news about their performance and less to bad, and ends up confident without anyone inside the head having planned it. The biased information search reported by Soldà and colleagues is the kind of behaviour such an account expects. That is a reading of the two literatures side by side, not a finding of either. The experiments measure what incentives do to confidence, and the question of why a mind would work that way sits one step beyond them.
Trivers and von Hippel's article was published with commentaries, and one takes a different line on self-deception. Ryan McKay and his co-authors write that the evolutionary view overlooks the subjective moral costs of fooling oneself and the question of how credible self-deceptive statements are to an audience. They propose a self-signalling interpretation instead, which they say can explain the ritualistic quality of some self-deceptive affirmations and the gap between what self-deceivers say and what they believe (Behavioral and Brain Sciences, 34(1), 34 to 35).
The difference is the audience. For Trivers it is other people, and the belief is a tool for moving them. For the commentators it is the self, and the statement is evidence about what kind of person one is. [Do Purchases Work as Self-Signalling](https://thewhyweproject.com/articles/do-purchases-work-as-self-signalling) follows that second idea into shopping.
The Book's Own Softer Mechanism and What Backs It
The Elephant in the Brain does not rest on the strongest version of Trivers's self-deception. Its preferred mechanism, self-discretion (pp. 88 to 89), involves no active lie and so no self-deception in the strict sense. Damaging information is kept available but given less psychological prominence, so it can be recalled and rarely is. The authors' proposed machinery is that pride rewards the neural pathways that bring a memory back and shame punishes them. The passage cites no study for that, and the vault's audit of the book tags the mechanism a conjecture. It is also a softer claim than Trivers's, since it asks for no false belief, only for the true one to be rehearsed less.
A related question, how much people can report about their own reasons for acting, is taken up in [You Do Not Know Why You Bought It](https://thewhyweproject.com/articles/you-do-not-know-why-you-bought-it), and [How Good Is Human Lie Detection](https://thewhyweproject.com/articles/how-good-is-human-lie-detection) covers what a listener can pick up from a speaker who believes the story.
The book's illustration is a worker who marginalises a rival with nothing quotable, a shift of the shoulder, a glance that lands elsewhere, all deniable as misreading (pp. 126 to 127). The authors add that if he introspected carefully he could notice what he was doing, "but why bother", since the less the mind's press secretary knows, the more convincingly it can deny.
Common questions
Is self-deception a persuasion tool?
In two experiments with 688 participants combined, people who expected to earn money by persuading a partner were more overconfident about their own performance, and the added confidence made them more persuasive. That supports an incentive effect. It does not show that evolution built self-deception for the purpose.
Who proposed that self-deception helps us persuade others?
Robert Trivers, with William von Hippel, in a 2011 article in Behavioral and Brain Sciences. They argued that self-deception hides the cues a conscious liar would leak, lowers the cognitive load of lying and limits retribution if the lie is found out.
Is there another explanation for the experimental results?
Alfred Mele argues that motivation can bias how people assess evidence with no intention to mislead. A commentary in the same journal issue offers a self-signalling account in which the audience is the self.
Sources
Simler, K., & Hanson, R. (2018). The Elephant in the Brain: Hidden Motives in Everyday Life. Oxford University Press. Ch. 5, pp. 73-89; pp. 126-127.
von Hippel, W., & Trivers, R. (2011). 'The evolution and psychology of self-deception.' Behavioral and Brain Sciences, 34(1), 1-16. doi:10.1017/S0140525X10001354
Schwardmann, P., & van der Weele, J. (2019). 'Deception and self-deception.' Nature Human Behaviour, 3(10), 1055-1061. doi:10.1038/s41562-019-0666-7
Soldà, A., Ke, C., Page, L., & von Hippel, W. (2020). 'Strategically delusional.' Experimental Economics, 23(3), 604-631. doi:10.1007/s10683-019-09636-9
Mele, A. R. (2001). Self-Deception Unmasked. Princeton University Press.
McKay, R., Mijović-Prelec, D., & Prelec, D. (2011). 'Protesting too much: Self-deception and self-signaling.' Behavioral and Brain Sciences, 34(1), 34-35. doi:10.1017/S0140525X10002608