Despite what pop psychology articles might suggest, detecting deception via body language – or even bodily functions such as respiration, heart rate and skin conductivity, the staples of the famed polygraph – is not in any way a reliable science. Such measures can indeed accurately pin point when someone is nervous – but not necessarily when they are lying.
When it comes to investigating and convicting criminals, British police rely on solid evidence. That is what detectives strive to collect – and what counts at court. And this is what the Metropolitan Police believe they have in the case of Alexander Petrov and Rusian Boshirov, the two Russian nationals accused of the poisoning of Russian emigre and former spy Sergei Skripal and his daughter Yulia in Salisbury last March.
On September 5, the police released details of a trip to the UK by the pair between March 2 and 4, the period when the Skripals were poisoned. They provided details of CCTV footage of the pair arriving in Salisbury, and walking in the vicinity of what is thought to be the scene of the poisoning at the time it happened.
This week, in a 25-minute interview with Russian state broadcaster RT, conducted by the editor-in-chief, Margarita Simonovna Simonyan – widely regarded as a close ally of Russian president Vladimir Putin – the pair insisted they were innocent tourists who worked in the sports nutrition business. They claim they simply travelled to London, and fitted in a couple of day trips to Salisbury.
I work in the department of psychology at the University of Portsmouth and my principal research is into deception and the detection of deception. In this capacity I have worked closely with the police. My colleagues and I at the university have conducted research into lies where the stakes are very high – this generally involves suspects in police interviews accused of serious crimes and our findings generally reflected those of laboratory studies.
We’ve found that different people react in vastly different ways when being questioned. These differences can occur between cultures and within cultures. Our experience when interviewing Russian participants in experiments is that they generally show less animation, facially and bodily, than British participants. Also, clever liars rarely tell a completely fabricated story, but instead tend to embed lies in an otherwise truthful account. On the other hand, someone who is telling the truth about key elements of their story, might still want to hide other elements.
For Petrov and Boshirov the interview has very high stakes – and throughout the interview they both appear very anxious and uncomfortable. At one point, the interviewer Simonyan even points out that they are sweating and turns up the air conditioning.
For the most part they appear to be keeping their hands under the desk. Many people associate fidgeting with deception – despite deception research consistently showing that liars actually tend to be less animated than truth tellers. Lying requires extra mental effort, which in turn results in a neglect of body language. Liars also tend to restrict their non-verbal behaviour, since they – like many other people – wrongly believe that fidgeting is associated with mendacity. But the fact that these men to a large extent hide their hands under the desk might suggest that they are seeking to give an impression of calmness.
It’s also important to note that the behaviour of an interviewer will often have an effect on the behaviour of interviewees. You may have noticed that in conversation your body language may end up mirroring that of your conversation partner and vice versa.
Either way, the only fact that can be established from the body language and demeanour of the pair in this interview is that they are worried. No more than that. For this reason, deception researchers have moved on from studying non-verbal behaviour in individuals.
Typically, in a police scenario, if more than one person is suspected of being involved in a crime, the suspects are split up and interviewed individually. The RT interview is different in that it is not a police interview – the questioning style differs quite substantially, and they are being interviewed together.
My Portsmouth colleague Zarah Vernham has conducted research into how truth tellers and liars behave when interviewed in pairs. She found that truth tellers tend to be more inclined to look at each other and add to each other’s stories or interrupt each other. Liars, meanwhile, tend to focus more on maintaining eye contact (it is also a myth that a liar cannot maintain eye contact) with the interviewer, with one as the main story teller and the other in a more subordinate role. Petrov and Boshirov both contribute to the dialogue and do on occasion interrupt or add to each other’s speech.
You couldn’t make it up
Truth tellers are more likely to include complications in their stories. This is largely because it might not occur to liars to do so. Complications happen in life (calling to mind the expression “you just couldn’t make it up”) and a truth teller will experience such complications.
Of course, all the above discussed research is published and available on the internet. It is therefore possible that Petrov and Boshirov could have studied this or been coached ahead of their appearance.
Did Petrov and Boshirov lie in their RT interview? Plenty of apparent contradictions to their story have emerged independently to suggest they may not have been telling the truth. But body language or facial expressions alone cannot be conclusive.
Written by Samantha Mann, Senior Research Fellow, Department of Psychology, University of Portsmouth