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Guilty? Proof is staring right at you
Publication Date : 27-12-2012
A specialist in facial expressions helps prosecutors
As he scanned a short report on an old case, veteran Beijing prosecutor Wang Guohui suddenly saw something that stopped him in his tracks. A wide smile crept across his face.
"It says here the suspect's bank card could be a key piece of evidence in the case," Wang said. "When I asked the suspect about it, the report says his expression and reactions changed. He stopped rubbing his hands and avoided eye contact."
The report was written by Jiang Zhenyu, a self-taught expert in microexpressions.
Microexpressions - which were popularised by the hit United States television series Lie to Me - are defined as a brief and involuntary facial or bodily movement that betrays an emotion.
Jiang had no knowledge of the case and based his observations on footage recorded during the interrogation of the suspect.
"He was right," said Wang, who is with the anti-corruption department of the capital's Changping district prosecution authority. "This tallies with the evidence we discovered during the investigation."
Wang is one of several prosecutors working with Jiang to improve the interviews of suspects in custody.
So far, they have given him access to six videos from solved cases with about 60 hours of taped interviews.
"Everyone has basic lines of emotions - a smile, a frown - as well as typical reactions when they are in a state of excitement," said Jiang, 33, whose day job is teaching computer science at the China University of Political Science and Law. "If they fake an emotion, they go against these lines. What I'm watching for is those reactions that happen so quickly that they can't be hidden."
Criminal suspects with something to hide, particularly corrupt officials, often attempt to suppress or mask feelings when they face interrogations, Jiang said.
"But they cannot stop the microexpressions that occur when prosecutors mention something innocuous that could easily be ignored, such as a bill, a check or a credit card. They give themselves away," Jiang said.
According to academic research, microexpressions display the seven universal emotions: disgust, anger, surprise, sadness, happiness, contempt and fear. In his 1999 book, Basic Emotions, US psychologist Paul Ekman added amusement, embarrassment, excitement, guilt, relief, pride, satisfaction, pleasure and shame to the list.
Jiang said that detectives and prosecutors could learn more from closely observing the faces of witnesses and suspects than from polygraph tests, also known as lie detectors.
After spending much of his higher education focused on technology, he studied computer science at college and later got a master's degree in communication, Jiang said he stumbled onto his passion by accident.
In 2007, he assigned his class the task of creating a digital image of a potato displaying an emotion. He was doing some online research when he came across an article about microexpressions. He was instantly hooked, and has since spent much of his spare time studying the subject.
At first, he held discussion groups for students at his college who wanted to learn more about the subject. Then, in March 2011, his hobby led to an offer of help to further his research from Changping's prosecution authority.
"In my reports [on the interrogation footage], I just say what I see, in the hope that the prosecutors take note and pay close attention to similar details in future cases," Jiang said. "I also suggest ways to ask questions that stimulate suspects and get them to open up."
He has also given several talks to lawyers with the anti-corruption department about communication techniques.
"Some experienced prosecutors can catch suspects in a lie through their expressions and gestures, but there has never been a professional system to guide our work before," said Jian Zhijian, a 30-year-old prosecutor at the department.
"My interrogation skills improved after I learned about microexpressions," Jian said. "Now I have some idea about how to cope with suspects who refuse to talk and those who are good at controlling their emotions."
Yang Lin, director of the department, also spoke highly of Jiang's contribution. But she added Chinese law does not allow those observations to be used as evidence in court.
"Academic research can't be used as evidence by the prosecution during a trial, but what we get from Jiang can be used as a reference for future interrogations," said Yang, who has 18 years of experience.
"Most of his analysis can be proved in practical interrogations, but that's not to say it's 100 per cent correct," Yang said. "Our cooperation project aims to provide a platform for Jiang to give prosecutors some academic advice. We discuss and approach a subject from different angles."
Yang also said police investigators and prosecutors should not blindly believe what is written in some books about facial expressions and body language, adding interrogation skills should be improved through experiments and discussions with academic researchers such as Jiang.
The Chinese Academy of Sciences and the People's Public Security University of China are also studying ways to apply microexpression training to the legal field.
Dai Peng, director of criminal investigation at the People's Public Security University of China, said the university has established a centre to study behavioural science and facial expressions and its potential for police investigations.
"Similar studies started appearing in the 1990s in China and are now being explored across the country," he said.
Jiang said that he has no illusions of becoming a consultant for authorities like Cal Brightman, the central character of TV series Lie to Me.
"I've never believed I'd be able to deal with cases directly, as that is forbidden under our laws, and I don't want to be a detective either," Jiang said.
"What I want is to make use of evidence from cases solved by prosecutors to do more analysis and give them reports to guide their work.