Tell me the truth, lizard – am I deceiving myself?

The human capacity for self-deception knows no bounds, but why do we do it? According to biologist Robert Trivers the simple answer is that it helps us have more children. He told Graham Lawton about the evolutionary benefits of lying

Psychologists been interested in self-deception for years, but you say we need a new science of self-deception?

Yes. Because the psychologists have not produced a theory. Self-deception lies at the heart of psychology, but if you read only psychology you will go blind and probably crazy before you discern the underlying principles. A functional view of self-deception has to come out of evolutionary logic. It has to be a pay-off in terms of reproductive success.

You argue that we deceive ourselves all the time, but why do we do it?

One reason is to better deceive others. Deceiving consciously is cognitively demanding. I’ve got to invent a false story while being aware of the truth, it’s got to be plausible, it cannot contradict anything you already know or are going to find out and I’ve got to be able to remember it so that I don’t contradict myself.

This takes concentration and I may give off cues that I’m lying. If I try to slip something by you I may not be able to meet your gaze. For linguistic cues, there are more pauses and fillers while I try to come up with my story. I’ll choose simple action words and avoid qualifiers. Another thing that gives us away us is the effort to control ourselves. Let’s say I’m coming to a key word in a lie. I tense up, but tensing up automatically raises my voice. That’s a very hard thing to fight.


So believing the lie yourself can help with this cognitive burden?

Yes. If I can render all or part of the lie unconscious I can remove the cues that I’m deceiving you. So that’s one kind of general reason to practice self-deception: to render the lie unconscious, the better to hide it.

What other types of self-deception are there?

Another broad category is that there is a general tendency to self-inflation. If you ask high school students are they in the top half of their class for leadership ability, 80 per cent will say yes; 70 per cent say they’re in the top half for good looks. It ain’t possible! And you cannot beat academics for self-deception. If you ask professors whether they’re in the top half of their profession, 94 per cent say they are.

So we self-deceive in order to give ourselves an ego boost?

The ego boost, again, is in order to deceive others. There is little intrinsic value in deceiving yourself without deceiving others.

What are the benefits of deceiving other people?

There are many, many situations in which you gain personal benefit. If you’re going to steal, you’ve got to lie to cover it up. If you’re having an affair you lie to protect the relationship Now, what do we mean by personal benefit? Ultimately it is measured in terms of reproductive success. But there isn’t a straightforward relationship between deception and reproductive success. For example, if I lie and I rise in the corporation, does this result in extra children? So we have to make a separate argument about why rising in the profession gives you benefits that translate into more surviving offspring.

There must be costs too?

Yes. The cost takes various forms. One is that you are more likely to be manipulated by others. A self-deceived person may be the only one in the room that doesn’t know what the hell is going on. Con artists use tricks to get your machinery of self-deception going, and then they control you. The general cost is you risk being out of touch with reality.

But still the benefits outweigh these costs?

Sometimes yes, sometimes no. Self-deception would not have evolved if the costs always outweighed the benefits.

What is going on in our brains when we deceive ourselves?

At the moment, not a lot is known about the neurophysiology. Much more is known about the immunology of self-deception. Here’s a vivid example of the cost of self-deception. Because of HIV, various aspects of homosexuality have been studied very intensely. It turns out the more you’re out of the closet, the better for you. If you’re HIV positive, you transit into AIDS much quicker if you’re in the closet about being homosexual.

Let’s return to evolution. Are humans the only species with the capacity for self-deception?

No, I do not think so. Lying is widespread throughout the animal kingdom, both between species and also within species. One example is mimics, species that are harmless and tasty but gain protection by resembling a poisonous or distasteful one. Psychologists are getting close to showing that monkeys practice self-deception.

Like humans, monkeys naturally associate members of their “in-group” with positive stimuli such as fruits, and out-group members with negative stimuli such as spiders.

Do children come into the world as self-deceivers or does it take a while to develop?

That is very tough to say. There’s evidence that deception in children starts at six months of age. By eight or nine months they have developed the ability to deny that they care about something that they do care about. But demonstrating self-deception is tricky.

Is it right that self-deception is correlated with intelligence?

Yes, at least for deception. The smarter your child is, the more he or she lies. In monkeys, the bigger the neocortex is, the more often they’re seen lying in nature.

In your new book you get into some quite serious stuff about how self-deception fuels warfare and other evils…

Regarding warfare, if you can get the group believing the same deception, you have a powerful force to impose group unity. And if you’ve sold the population a false historical narrative, say “the German people need room in which to live”, then it’s relatively easy to couple marching orders to the delusion.

Tell me about the relationship between self-deception and religion.

It’s complex. At one extreme you could say religion is complete nonsense, so the whole thing is an exercise in self-deception. I was raised as a Presbyterian and I occasionally attend. I stand back and I read the creed that I was taught as a child and it’s utter, utter nonsense. But could it have spread so far by self-deception alone? Religion has been selected for. It has given many benefits to people – health benefits, cooperative benefits. So I take an intermediate position.

Are you a self-deceiver?

I end the book with a chapter on fighting our own self-deception. I’ve been remarkably unsuccessful in my own case. I just repeat the same kinds of mistakes over and over. If you ask me about my self-deception, I can give you stories, chapter and verse, in the past. But can I prevent myself doing the same damn thing again tomorrow? Usually not, though in my professional life as a scientist, I feel that I probably practice less self-deception, I’m more critical of evidence, a little bit harder nosed.

“I have been remarkably unsuccessful at fighting my own self-deception”

You could be deceiving yourself about that.

Absolutely.

Profile Robert Trivers is one of the world’s best-known evolutionary biologists. His work influenced sociobiology, evolutionary psychology, behavioural ecology and Richard Dawkins’s concept of the selfish gene. He is professor of anthropology and biological sciences at Rutgers University in New Brunswick, New Jersey. His latest book, titled The Folly Of Fools in the US and Deceit And Self-Deception in the UK, is out this month