December 7, 2021

I, Science

The science magazine of Imperial College

Is the ability to lie convincingly a central aspect of (social) survival? Naomi Stewart dives into the evolution of the deceptive human nature.

Bill Clinton at podium

I did not have sexual relations with that woman”, then-President Bill Clinton proclaimed on live television. Each drawling word was punctuated with a pause for effect, his index finger wagging in perfect unison.

Of course we all know now, that he had had sexual relations with that woman. Even as one of the world’s prominent figures at the time, Bill Clinton told a lie. Lies can be considered the intention to deceive others for a perceived benefit, and in fact, all humans lie to varying degrees and intensities.

The 18th century German philosopher Immanuel Kant was famously against lying in any circumstance, “By a lie a man throws away and, as it were, annihilates his dignity as a man”. Many others have postulated that lies are entirely detrimental to the liar, lied-to, and society at large, especially as it removes the ability for consent or to make fully informed decisions. Still, the perception of lying as qualitatively good or bad has no firm moral answer, and despite its taboo social nature, it exists in all cultures and throughout human history – from the Trojan Horse of the Greeks to the nervous student cheating on an exam question.

At the core of it, we all know why we lie – to conceal the truth and present an alternate scenario that we believe is somehow better. I imagine if you honestly think about it, you will realise you have probably already done it today. “I ran five kilometres this morning!” …we both know it was only three and a half. But how and why has this belief evolved, that a periodic yet pervasive misrepresentation of reality is beneficial?

Lying is just one of the many behaviours of deception, which are quite common throughout the natural world. Four levels of increasingly complex deceptions include:

  1. Programmed false appearance: Camouflage or false markings; some moths have wings that look like owls eyes when they open.
  2. Programmed false behaviour: Involuntary deception requiring external triggers; some birds feign injury to attract attention when a predator is around their young.
  3. Learned false behaviour: Behaving a certain way, having learned it elicits certain responses; a dog may fake injury because it invokes sympathetic human responses.
  4. Learned planned deception: Conscious attempts to manipulate other’s beliefs and actions; chimpanzees and baboons do this at a simple level, and of course so do humans, at more highly functioning and complex levels.

The last two levels both involve what some psychologists refer to as Machiavellian skill or intelligence – the capacity to think about other’s responses when deciding how to act, and factor those responses into your decision. However, it is only in the fourth level where ‘lies’ are found.

The intensity of a lie can range from ‘white lies’ which are of minimal impact (and can even be beneficial to others) to extensive, complex manipulation like embezzlement or war crimes. Their expression can range from spoken lies or obfuscated truths, to lies of omission, and can also include body behaviour.

Research on the evolution of lying in humans has largely been around the spectrum and causes of deliberately planned deception. Much research has also been done on the circumstances surrounding when and why people lie, and to what extent; it is a heterogeneous and fascinating field of causality. The propensity to lie is tied to factors like gender, culture, age, and genetics, varying widely, even in one person. For example, women are less likely to lie than men if the lie comes at a great cost to someone else, and are more likely to lie altruistically. They are also less likely to lie than men for smaller economic gains, but lie just as much when it comes to big ‘wins. However, regardless of gender, the closer someone feels to another person the less likely they are to lie overall, even for large economic gains.

The act of lying itself requires fairly complex cognitive functions that so far only humans and certain primates have. Biologically speaking, this makes sense; increased abilities to understand and manipulate the world require increased neural processing (to create the ‘story’ of the lie, to have cognitive space to store the memory of the lie, etc.), and would thus be found in organisms with the capacity for such. Indeed, recent data show that the frequency of deception is directly related to the size of the neocortex – a recently evolved section of the mammalian brain that processes, amongst other things, conscious thought, language, and reasoning.

quote1It has been estimated that half of the lies humans tell are to secure a greater amount of resources. By pretending to be more friendly or in need than they actually are, people can acquire resources – for example, scamming elderly people out of their savings by pretending to be in desperate need for an emergency. People could also feign flirtation or flattery, seducing potential partners; if they play their cards right, this behaviour increases their chances of reproduction and thus biological fitness.

Evolutionary biologist Robert Trivers argued that selection pressures actually favour “subtle cheaters” over those who are cheated on, indicating that the behaviour of lying is an inherited evolutionary trait, not just a learned behaviour. In a later study on identical twins, he also found that genetic models were actually better predictors for lying behaviour than environmental ones.

Despite this, it has not been determined precisely when Machivellian intelligence arose in the evolution of higher primates. Some researchers have argued that denial and self-deception evolved necessarily for us to knowingly process and navigate the complexity of the world, “this sense of unity as a coping strategy is really a deception or illusion, in that it imposes perceived order. Thus, the biology of deception has been an important development leading to man as a cognitive creative being.”

Although we can see and experience the negative effects, and certainly dislike when it happens to us or we are discovered in the act (Bill Clinton ended up being charged with a crime and impeached for his infamous lie!), lying is nonetheless a double-edged sword in which there are and have been many practical evolutionary benefits. At the biological level, if lying allows you to acquire more resources for yourself and increase your fitness, you are more likely to survive and pass on your genes. Being able to manipulate your environment and the responses and actions of others around you through lying does seem to favour increased abilities to navigate and gain from the world, even if it comes at the price of being caught or exposed.

Moral quandaries aside (Kant forgive us), lying is not going away any time soon. Besides, did it serve any purpose to know what Bill was up to? Do we always want to know what people are thinking? Could we even imagine an over-simplified, algorithmic world in which there is no option but to tell the truth all of the time?

It seems perhaps the best way forward is to understand and find practical uses for this naturally evolved and periodically advantageous behaviour, both as individuals and societies. What that involves, however, may just very well continue to be up to our own cost-benefit analyses and decisions about what’s optimally beneficial in the end. So maybe run all five kilometres, but leave the concealment of infidelity to the presidents.

Naomi Stewart is studying for an MSc in Science Communication

Image by Joseph Stohm