What makes us judge people as suspicious? There are thousands of papers published by folks from vision and computing science, who try to find a ‘holy grail of security’ - automatic system for detecting hostility. But there is surprisingly small number of papers looking at psychological aspects of detecting suspicious behaviours. Sure, there is a legion of self-help books, NLP-breed mutant-books on earning £10K per week in 5 simple steps and ‘reading people like books’ or common-sense guidelines. These are often ultra-simplistic approaches, missing the point entirely. Science frequently shows us, that counter-intuitive approach turns out to be true. For example, lets take a topic of lying and detecting deception - one of the very important questions I am looking at in my current project.
You probably assume that people who are experts in interrogation (e.g. military intelligence) would be better in spotting lies than a random person without any expertise in such field. Right? Well, you are wrong. Turns out that novices are frequently more accurate than experts. Why might this be? First, expertise often entails other factors such as age, high motivation, and access to other sources of information that accompany expert’s occupation. Also, experts usually gain little self-correcting feedback when they commit false-negatives (i.e. believing a dishonest person is honest) and also when they commit false-positives (i.e. believing an honest person is dishonest). So they may become overly confident of their detection abilities. Together, these factors can impair judgement much more than in case of novice, who looks at the situation without any preconceptions. If you run a simple experiment comparing experts with non-expert, you would most likely confirm those assumptions (as others did - see Burgoon et al., 1994 - a classic on interpersonal deception).
Another example: you would assume that when you are suspicious about others, you are better in detecting dishonesty or lie (because presumably you are more sensitive to behavioural cues). Wrong again. First - it will be very obvious to the skilled observers that you are suspicious about them, so they can react and adjust their behaviour, and trick you better. There is actually a lot of ‘non-verbal leaking’ coming from the person, who is suspicious about others, and this is not good when you interact with a smart deceiver (who has time to change his communication strategy). Secondarily - if you are suspicious about others, you are also lie-biased, you perceive people as less trustworthily. So you commit much more false-positive judgements than observer who is not suspicious about others. Again, this cause you to focus overly on unimportant information, overload your cognitive system, and possibly omit the real suspect (e.g. in the airports screening situation, where there is massive crowd to monitor). So overall - observers who are suspicious about others are less accurate in detecting deception and truth telling than non-suspicious observers. This ESPECIALLY applies to EXPERTS who seem to make a lot of stereotyped and biased judgements based on their biased experience, which blends badly with their suspicious-receivers approach (see the first point I made).
This doesn’t mean that we need to get rid of all the airport security every year to keep the security fresh. Because there are advantages of being an experts as well - with experience you get better grab of questioning strategies, that can help you a lot in reading other people intentions. You know, those simple and apparently meaningless questions you get asked on airports randomly? Those are just dummy questions, nonverbal triggers, to facilitate any hidden, bad intention that you might ‘nonverbally leak’. With experience, you also get better in reading nonverbal signals, although this one is more unclear, and seem to be related with many other factors.
There is another level - multisensory integration of verbal and non-verbal cues when you are trying to decode the suspect, but this is a completely different story...
