Why do we lie?

It's not just bad behaviour- deception is a product of evolution and it gives your brain a real workout

Your dog really did eat your homework, and you have no idea who took the last
biscuit from the sweet jar. Lying is in your nature, but don’t worry – it’s in the nature of most humans. It’s a technique that has evolved over billions of years, so it turns out you might not actually have that much to feel bad about.

Humans are social creatures, and we have our giant brains to thank for this. They
evolved to be so large because we needed the extra space to be successful at
communicating with others and keeping our social group happy. This has a lot of advantages. If you can build bonds with other humans you can access more resources because your friends and family will share food and shelter, helping you out when you need it. But to keep these close connections sometimes we need to lie. 

Throughout hominid history it has been a genetic advantage to be a good liar, as it supports social bonds, and therefore you are more likely to survive and pass on your genes. Bending the truth, playing fast and loose with the facts, telling a tall tale – whatever you call it, lying is something that most individuals in our species find really easy.

Although deception is frowned upon by society, it actually evolved as a way to
fine-tune our social skills and strengthen our relationships. Have you ever told a friend that you really loved the dinner they had cooked for you? Or maybe you have lied to your mum about accidentally breaking something in the kitchen? That’s these evolutionary mechanisms kicking in, and whether it was to protect your reputation or just avoid upsetting someone, it probably worked well to protect your relationships (if you didn’t get caught that is).

When do we learn to lie?

It’s thought that we learn how to lie much younger than we probably think, with some research suggesting it may have begun as early as six months old. Over the years we perfect the art, and some estimates suggest by the time we are in college we may be lying to our mothers once every five interactions.

The developmental model of lying was first proposed by researchers Victoria Talwar and Kang Lee. Their work shows that children between the ages of two and three start telling primary lies – basic deceptions to cover up mistakes or bad behaviour – but without considering whether the listener will actually believe the lie. Around the age of four children start to tell secondary lies, more crafted and complex lies that are more believable. By age seven or eight children start telling tertiary lies, using consistent facts and follow-up statements. This is an ability that will stay with them for the rest of their lives.


 This article was originally published in How It Works issue 120, written by Charlie Evans


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