Most experts on nonverbal communication are called upon, at some time in their career, to analyse footage where significant events have taken place and where we know how the person concerned was implicated, what they did, and whether they are guilty or not. We are often asked to view the footage and to identify any ‘telltale’ signs of deception or guilt. These are problematic enough because they allow the researcher to identify the nonverbal cues that they consider most significant with regard to deception. The problem, however, in detecting deception is that there are very significant individual differences in most of the behaviours of interest and any accurate detection requires mapping out, and understanding, the baseline characteristics for that individual. It’s very misleading to just jump into a small bit of footage and point to one or two behaviours that may be associated with anxiety and fear of detection, or fresh cognitive planning, without all of the required background knowledge. Of course, it’s even more problematic when you don’t know whether someone is guilty or not because you may be helping to determine their fate or influencing public opinion towards the person. There are a number of cues and signals that are associated with certain emotional experiences, and with thinking on the spot, but their identification requires careful study of the individual in question. Without this psychology may indeed be guilty of overreaching.

There is evidence from psychology that people do make very quick judgements about other people. A study by Willis and Todorov from Princeton found that when they presented participants with photographs of people and asked them to judge how ‘attractive’, ‘likeable’, ‘competent’, ‘trustworthy’, and ‘aggressive’ they were, participants seemed to do this within one tenth of a second - and particularly for the dimension of ‘trustworthiness’, but also for the others dimensions including ‘likeability’. It is a most curious result in a way because we (i.e. people) seem quite prepared to make judgements about others after minimal exposure, which may then set up a bias for the processing of other information from that person. Of course, this study just presented images of faces to people - in real life it gets a lot more complicated than that because there are multiple sources of information which may conflict and hopefully, for the good of everybody, slow this process down!

One important cue to deception is the spontaneous and unconscious hand movements that accompany speech. These movements appear to decrease in frequency when people are lying, and are often inhibited altogether. When gesticulation isn’t fully inhibited, the stroke phase of the gestural movement, that is the meaningful section which is communicative, appear to shorten. All of this, of course, require that you have a baseline of gestural behaviour for the individual in question. There are very significant differences in gesture frequency and duration between different individuals so you need to spot divergences from the baseline within the individual. I consider this issue in more detail in my book ‘Rethinking Body Language’ (Routledge) and outline the science behind it there.

This is a really interesting question. Some people seem very sensitive to nonverbal communication because they have learned through experience within the family, within their work setting, within everyday life, that these cues are important for reading people, and they have become very sensitised to them. I sometimes play videos of facial expression with some micro-expressions popping up in the middle of them to lecture theatres full of students and the divergence in perception and response is enormous. Some perceive and identify the micro-expression correctly, some see nothing at all. The fleeting expressions passed them by completely. Specifically what experiences give rise to these abilities remains to be conclusively answered. A few years ago I did some research on people’s ability to decode spontaneous hand movements, which are described in technical jargon as ‘iconic gestures’. The Individual differences here were huge. Again, I have no idea as to where these individual differences come from, but I did explore the communicational value of these movements in my book ‘Rethinking Body Language’. We all do need to be more sensitive to these dynamic cues, as they are very important indeed.

They make it much more difficult! Anything which interferes with the musculature underlying facial expressions, like Botox, is going to affect the generation of facial expressions and therefore make the judgment of emotion from the highly revealing but very brief expressions, micro expressions, incredibly difficult. Another very interesting question is what the long-term effects of cosmetic surgery will be on how human beings attend to each other in conversation. If you learn that facial expression is being inhibited through surgery and no longer as expressive or revealing, do you stop attending to the face as the primary focus of regard, and what are the long term implications of this?

People often miss the very brief but revealing facial expressions that flit across the face. They see a smile and they assume that a person is happy. But a smile is both a genuine expression of positive emotion and a mask to cover negative emotion. The secret is to watch how the smile fades. If it fades very quickly it’s more likely to be a deliberative expression to cover up negative emotion. Try to notice the underlying expression as the smile fades. That’s something people often miss!