The first time they witness their child tell a lie, many parents panic. Why would a toddler as young as two years old say or do anything dishonest? Is it a sign they’ll turn into a deceptive, untrustworthy, possibly even amoral adult?
“I’m always very happy to hear about small children lying,” says Kang Lee, psychology professor at the University of Toronto. “Parents find it worrying, but it’s actually an important sign of normal, healthy development.”
Lee is an expert on lying in children, having devoted 30 years to researching this fascinating, and previously unexplored subject. His groundbreaking work has led to a series of major advancements including a law reform on the treatment of child witnesses, a transformation in the way behavioural problems in children are diagnosed and treated, and the development of technology now used by millions to monitor people’s health via smartphones.
“I’m very lucky that the University of Toronto has supported me in exploring all my ideas, helping me get funding for my projects and the patents,” he says. “Its reputation attracts an amazing pool of students I can choose from to help me, so we can do all sorts of incredible things.”
The scope of his discoveries is far beyond anything he could have envisaged at the start of his career, when he was searching for an area to research for his doctoral thesis. “I came across a book called Studies in Deceit, a classic text from 1928 that looked at kids cheating at a young age, but had almost nothing about lying,” he says. “I looked at the literature since, and found fewer than 20 papers, so I realised I could make a real contribution.”
Since then, he has studied thousands of children all around the world to ascertain how they learn to lie, and how this fits into their development of social and moral understanding. The results fly in the face of everything we might assume – for instance, that children learn to lie after the age of five, that they are bad at it, and that if younger children do it, it’s a major red flag.
In fact, all three assumptions are incorrect. One study involved Lee and his team telling children that if they could guess the numbers on the cards face-down on the table in front of them, they would win a big prize. The adult then left the room and, of course, the vast majority of children peeked at the card. When they returned and asked the child if they’d peeked, 30% of two-year-olds, 50% of three-year-olds, and more than 80% of four-year-olds lied.
Rather than being psychopaths in the making, the children who begin lying earlier are those “who tend to have much better cognitive abilities”, says Lee. “Lying requires self control and ‘theory of mind’ – the capacity to understand another person’s intentions and beliefs.” It can also be very difficult for adults to detect children’s deception, because they are adept at lying without changing their facial expressions.
One of Lee’s most startling findings was that children knowing that lying is wrong has no bearing on whether they do it. “That was a very big surprise,” he says. It had unexpected implications for the way child witnesses give evidence in court. Previously, they underwent a competency examination, in which their reliability was determined by their understanding of right and wrong.
“We were able to prove that the examination was useless,” he says. “We discovered something else – that if you ask a child to promise to tell the truth, they are significantly more likely to do so, even if they don’t really understand what a promise is. The idea of a promise is a superpower.” In 2006, law in Canada was reformed, ditching the requirement for a child to take a competence examination to find out whether they know what a lie is and that lying is morally wrong. Instead, a child will be required to promise to tell the truth.
It was just the first of several innovations Lee has made in his 20 years at the University of Toronto. Another is a far deeper understanding of children with behavioural issues, who lie often. Previously, they had been assumed to have little moral understanding, and most interventions were based on the concept of trying to teach them this. However, Lee’s research showed this approach was based on a fallacy. “Their problem isn’t morality, it’s emotional control,” he says. “The way to help them is to teach them skills and activities to inhibit negative behaviours.”
More recently, he developed an innovative lie detector, called transdermal optical imaging. This extraordinary technology can measure physiological changes to the human body – such as heart rate and blood pressure – simply by looking at a person’s face. “It measures blood flow under the skin,” says Lee. “When we lie, our blood flow changes.”
It was entirely by chance that he realised the full potential of his invention. “I was invited to Boston to give a talk to the US Department of Homeland Security and, afterwards, one of the officers told me: ‘If you just use this technology for lie detection, it will be a waste,’” he says. “She said it should benefit more people than the government.”
The conversation sparked the idea of trying to use it in healthcare. Now, it forms the basis of a cutting edge AI system called DeepAffex, which processes video images of a user’s face taken on a smartphone and produces a host of information about their health, from heart rate, blood pressure and BMI, to their risk of type 2 diabetes, heart attack and stroke. “About 20 million people around the world use it,” he says.
His next project is expanding the app’s ability to measure mental as well as physical health. “In time, we will be able to use people’s blood flow to make predictions about whether they have anxiety disorder, depression or stress,” he says.
But he hasn’t abandoned his first fascination, childhood dishonesty – he’s currently researching academic cheating among children. “It’s enormous amounts of fun,” says Lee.
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