In Quirkology, Prof Wiseman describes his work into the psychology of deception, and reveals how to tell when someone is lying.

But how good are your lie detection skills?

Prof Wiseman recently conducted two interviews with the Editor of New Scientist, Jeremy Webb. Each time Jeremy was asked about his favourite film. In one interview he told the truth, and in the other he lied.

Watch the two interviews below, and decide which you think is the pack of lies.

Interview A

Interview B

Which was the lie? Find out by watching the clip below.

In 2007, over 16,000 people took part in an online Quirkology experiment to discover if they could detect Jeremy's lie. Some of them were shown both the video and soundtrack, whilst others only heard the soundtrack. Would this affect the results? Finally, before taking part in the study, everyone was asked to indicate whether they had a background in science or the arts. Would scientists prove to be better or worse at detecting the lies?

Prof Wiseman has carried out this experiment several times in the past, with previous interviewees including the political interviewer Sir Robin Day, and Hollywood actor Leslie Nielsen. The results of this work showed that people are not very good at detecting lies.

In this new experiment, around 70% of them correctly identified the lie - suggesting either that participants were good lie detectors or Jeremy is not a very good liar! There was no difference between those who saw the video and those who only heard the soundtrack, suggesting that the visual signals (such as facial expressions and body language) do not help people detect lies. Finally, we found that people with a science background were the best lie detectors, followed by visual artists, engineers, and finally mathematicians.