Life & Style

Transcript: Can You Really Tell If a Kid is Lying? By Kang Lee at TED

So let’s start with undergrads and law school students, who typically have limited experience with children. No, they cannot detect children’s lies. Their performance is around chance.

Now how about social workers and child-protection lawyers, who work with children on a daily basis? Can they detect children’s lies? No, they cannot.

What about judges, customs officers and police officers, who deal with liars on a daily basis? Can they detect children’s lies? No, they cannot.

What about parents? Can parents detect other children’s lies? No, they cannot.

What about, can parents detect their own children’s lies? No, they cannot.


So now you may ask: Why children’s lies are so difficult to detect. So let me illustrate this with my own son, Nathan. So this is his facial expression when he lies.


So when children lie, their facial expression is typically neutral. However, behind this neutral expression, the child is actually experiencing a lot of emotions, such as fear, guilt, shame and maybe a little bit of liar’s delight. Unfortunately, such emotions are either fleeting or hidden. Therefore, it’s mostly invisible to us.

So in the last five years, we have been trying to figure out a way to reveal these hidden emotions. Then we made a discovery.


We know that underneath our facial skin, there’s a rich network of blood vessels. When we experience different emotions, our facial blood flow changes subtly. And these changes are regulated by the autonomic system that is beyond our conscious control. So by looking at facial blood flow changes, we can reveal people’s hidden emotions. Unfortunately, such emotion-related facial blood flow changes are too subtle to detect by our naked eye. So to help us reveal people’s facial emotions, we have developed a new imaging technology we call “transdermal optical imaging.”

To do so, we use a regular video camera to record people when they experience various hidden emotions. And then, using our image processing technology, we can extract transdermal images of facial blood flow changes. And by looking at transdermal video images, now we can easily see facial blood flow changes associated with the various hidden emotions. And using this technology, we can now reveal the hidden emotions associated with lying, and therefore detect people’s lies. We can do so noninvasively, remotely, inexpensively, with an accuracy at about 85%, which is far better than chance level.


And in addition, we discovered a Pinocchio effect. No, not this Pinocchio effect. This is the real Pinocchio effect. When people lie, the facial blood flow on the cheeks decreases, and the facial blood flow on the nose increases.

Of course, lying is not the only situation that will evoke our hidden emotions. So then we asked ourselves, in addition to detecting lies, how can our technology be used? One application is in education. For example, using this technology, we can help this mathematics teacher to identify the student in his classroom who may experience high anxiety about the topic he is teaching so that he can help him.


And also we can use this in health care. For example, every day I Skype my parents, who live thousands of miles away. And using this technology, I can not only find out what’s going on in their lives but also simultaneously monitor their heart rate, their stress level, their mood and whether or not they are experiencing pain. And perhaps in the future, their risks for heart attack or hypertension.

And you may ask: Can we use this also to reveal politicians’ emotions? For example, during a debate. Well, the answer is yes. Using TV footages, we could detect the politicians’ heart rate, mood and stress, and perhaps in the future, whether or not they are lying to us.


We can also use this in marketing research, for example, to find out whether or not people like certain consumer products. We can even use it in dating. So for example, if your date is smiling at you, this technology can help you to determine whether she actually likes you or she is just trying to be nice to you. And in this case, she is just trying to be nice to you.


So transdermal optical imaging technology is at a very early stage of development. Many new applications will come about that we don’t know today. However, one thing I know for sure is that lying will never be the same again.

Thank you very much.


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By Pangambam S

I have been a Transcriber and Editor in the transcription industry for the past 15 years. Now I transcribe and edit at If you have any questions or suggestions, please do let me know. And please do share this post if you liked it and help you in any way.