How self-deception allows people to lie

Self-deception can fool us into believing our own lies – and even make us more convincing.The media today is full of people who have lived a lie. 

There’s Elizabeth Holmes, the biotech entrepreneur, who in 2015 was declared the youngest and richest self-made female billionaire. She now faces 20 years in prison for fraud. Then there’s Anna Sorokin – aka Anna Delvey, who pretended to be a German heiress, and subsequently fleeced New York’s high society of hundreds of thousands of dollars. And Shimon Hayut, aka Simon Leviev – the so-called Tinder Swindler. 

What marks all of these people is not just the lies they told others – but the lies they must have told themselves. They each believed their actions were somehow justifiable, and – against all odds – believed they would never be found out. Time and again, they personally seemed to deny reality – and dragged others into their scams. 

You might hope that this kind of behaviour is a relatively rare phenomenon, restricted to a few extreme situations. But self-deception is incredibly common, and may have evolved to bring some personal benefits. We lie to ourselves to protect our self-images, which allows us to act immorally while maintaining a clear conscience. According to the very latest research, self-deception may have even evolved to help us to persuade others; if we start believing our own lies, it’s much easier to get other people to believe them, too. 

This research might explain questionable behaviour in many areas of life – far beyond the headline-grabbing scams in recent years. By understanding the different factors contributing to self-deception, we can try to spot when it might be swaying our own decisions, and prevent these delusions from leading us astray. 

Safeguarding the ego 

Any psychologist will tell you that studying self-deception scientifically is a headache. You can’t simply ask someone if they are fooling themselves, since it happens below conscious awareness. As a result, the experiments are often highly intricate. 

Let’s begin with the research of Zoë Chance, an associate professor of marketing at Yale University. In an ingenious experiment from 2011, she showed that many people unconsciously employ self-deception to boost their egos. 

One group of participants were asked to take an IQ test, with a list of the answers printed at the bottom of the page. As you might expect, these people performed considerably better than a control group who did not have the answer key. They did not seem to recognise how much they had relied on the ‘cheat sheet’, however – since they predicted that they would do equally well on a second test featuring another hundred questions, without the answer key. Somehow, they had fooled themselves into thinking that they had known the solutions to the problems without needing the helping hand. 

To be sure of this conclusion, Chance repeated the whole experiment with a new set of participants. This time, however, the participants were given a financial reward for accurately predicting their results in the second test; overconfidence would come with a penalty. If the participants were conscious of their behaviour, you might expect this incentive to reduce their overconfidence. 

In reality, it did little to puncture the participants’ inflated self-belief; they still fooled themselves into thinking they were smarter than they were, even when they knew that they would lose money. This suggests that the beliefs were genuine and deeply held – and surprisingly robust. 

It’s not hard to see how this might apply in real life. A scientist may feel that their results were real, despite the use of fraudulent data; a student may believe they earned their place at a prestigious university, despite cheating on a test.

Moral sincerity 

The use of self-deception to enhance self-image has now been observed in many other contexts. For instance, Uri Gneezy, a professor of economics at the University of California, San Diego, has recently shown it can help us to justify potential conflicts of interest in our work. 

In a 2020 study, Gneezy asked participants to take on the roles of investment advisors or clients. The advisors were given two different opportunities to consider – each of which came with different risks and different payoffs. They were also told that they would receive a commission if the client opted for one of the two investments. 

In one set of trials, the advisors were told about this potential reward at the very start of the experiment, before they started considering the different options. While they were ostensibly picking the best choice for the client, they were much more likely to go with the choice that was favourable to themselves. 

In the rest of the trials, however, the advisors were only told of this potential reward after they had been given some time to weigh up the pros and cons of each. This time few chose to let the reward influence their decision; they remained honest to their goal of giving the best advice to the client. 

To Gneezy, the fact that the knowledge of the personal benefits only influenced the participants’ decision in the first scenario suggests that their self-deception was unconscious; it changed the way they were calculating the benefits and risks without them being aware of the bias, so that they could feel that they were still acting in the clients’ interest. In the second scenario, it would have required a complete change of mind, which would have been harder to justify to themselves. “They just couldn’t convince themselves that they would be acting ethically,” he says.

In this way, self-deception is a way of protecting our sense of morality, says Gneezy. “It means that we can continue to see ourselves as good people,” he says – even when our actions would suggest otherwise. 

This form of self-deception might be most obviously relevant to financial advisors, but Gneezy thinks it could also be important for private healthcare. Despite having good intentions, a doctor could unconsciously deceive themselves into thinking the more expensive treatment was best for the patient – without even recognising their self-deception, he says. 

Persuading ourselves, persuading others 

Perhaps the most surprising consequence of self-deception concerns our conversations with others. 

According to this theory, self-deception allows us to be more confident in what we are saying, which makes us more persuasive. If you are trying to sell a dodgy product, for instance, you will make a better case if you genuinely believe it is a high-quality bargain – even if there is evidence to suggest otherwise. 

This hypothesis was first proposed decades ago, and a recent paper by Peter Schwardmann, an assistant professor of behavioural economics at Carnegie Mellon University, US, provides some strong evidence for this idea. 

Like Chance’s study, Schwardmann’s first experiments began with an IQ test. The participants weren’t given the results, but after the test was finished, they had to privately rate how well they thought they’d done. They then took a test of persuasion: they had to stand before a jury of mock employers and convince the panel of their intellectual prowess – with a potential 15 euro ($16, £12.80) reward if the judges believed that they were among the smartest in the group. 

Some people were told about the persuasion task before they rated their confidence in their performance, while others were told afterwards. In line with the hypothesis, Schwardmann found that this changed their ratings of their abilities: the prior knowledge that they would have to convince others resulted in greater overconfidence in their abilities, compared to those who had not yet been told. The need to persuade others had primed them to think that they were smarter than they really were. 

He describes this as a kind of “reflex”. Importantly, Schwardmann’s experiments showed that the self-deception paid off; unfounded overconfidence did indeed increase people’s ability to persuade the mock employers.