A2 Psychology at Spalding Grammar School

Some forensic psychologists prefer biological measures to detect lying. A polygraph is a device that measures changes in skin conductivity and heart rate when the suspect becomes tense (ie is lying). It’s possible to fool polygraphs by making yourself tense up by digging nails into your own skin, etc. Also, some groups oppose polygraphs, since they claim they lead to false convictions. Drugs like Sodium Pentathol are advertised as “truth serums” but only make the suspect relaxed and careless – they won’t make you say anything against your nature and don’t force people to tell the truth. 

Behavioural psychology has a lot to contribute to the subject of spotting liars. Common signs (or CUES) of lying include:

• Avoiding eye contact
• Touching face, throat or mouth
• Timing of emotional gestures (like smiles) – too late, too slow or separate from speech
• Placing objects as a “barrier” in front of the questioner
• Repeating the wording of the question in the answer
• Discomfort with silence leads to adding unnecessary details to an answer
• The BBC's h2g2 website has a helpful page on this topic
• There's also some good information on this WikiHow page
• This web page from Life Training Online has some interesting explanations of Behaviour Analysis
• This page on Blifaloo has a simple explanation of Visual Accessing Cues as a way of detecting lies

Police officers tend to think they are good at spotting lies when they are interviewing suspects. They often claim that suspects reveal they are lying by minor body language or by being inconsistent under repeated questioning. It’s very hard to test this because it’s not permitted for the public to look at recordings of police interviews with suspects. This is because a suspect is innocent until proven guilty and even suspects have a right to privacy until their case comes to court.

Samantha Mann et al. (2004) carried out a field experiment testing 99 Kent Police officers. There were 24 females and 75 males, with a mean age of 34. The majority (78) were detectives, but some were in training, traffic officers or uniformed response officers. Before beginning, the officers filled out a questionnaire about their experience of detecting liars, what they look for, etc.

The officers watched 54 video clips of 14 suspects answering questions about crimes. The clips varied between 6 seconds and 145 seconds and all showed the suspects’ head and upper body, making it easy to spot expressions and movements. The suspects had been chosen because, for each, there was separate evidence that established whether they were telling the truth or not. After each clip, the officers had to note down:

1. whether they thought the suspect was lying or not
2. how confident they were about their judgment
3. what cues they had used to reach this decision

The officers spotted lies on average 66% of the time and identified truthful statements 64% of the time. Both of these scores are higher than chance (which would be 50% accuracy). There was a positive correlation between the two scores, meaning that people who were better at spotting lies were also better at identifying the truth. There was also a positive correlation between how many years of experience the officer had at interviewing suspects and their score for detecting lies.

The most frequently cited cue to detect lying was gaze and eye contact. The second most cited cue was body movement and gestures. The officers also pointed out inconsistencies in stories and fidgeting. However, the best lie detectors cited story cues (inconsistencies, contradictions, faulty details).

Lots of research has been carried out into this topic, but a lot of it involves asking officers to interview college students who may or may not have carried out a “mock crime” (eg Hartwig et al., 2004). This study actually lets the officers make judgments about real suspects. They performed well, but we still don’t know if they performed better than members of the public. Unfortunately, the videotaped interviews are too sensitive to be shown to non-police officers. Samantha Mann also noticed that the officers had many faulty ideas about deception cues that they’d picked up from police manuals, traditional practices and even TV shows.

This web page from PsyBLOG separates the myths from the facts about detecting lies.

The police are often accused of using too much force to obtain confessions, perhaps because they are certain on other grounds that the suspect is guilty, perhaps because they are under political pressure to get a conviction quickly. In Britain, the 1984 Police And Criminal Evidence (PACE) Act insists that all interviews must be recorded, in triplicate, on special machines and one copy must be kept unopened until the trial. Suspects can no longer be interrogated through the night or threatened in various ways. In America, the police have greater freedom to interrogate a suspect, as do British police under the Prevention of Terrorism Act. Interrogation is more accusatory than interviewing – the police officer tells the suspect they are guilty and it’s up to the suspect to deny it. Despite what you see on TV, police are required to be patient and non-abusive towards a suspect, but there are still very COERCIVE techniques than can be used to get a confession.

A particularly influential manual for interrogation in police or military settings has been the REID TECHNIQUE, developed by Fred Inbau & John Reid (1986), which uses persuasive techniques including deceit, trickery and psychological manipulation to break down suspects’ resistance and increase the desire to confess.  The authors frankly admit these techniques would be seen as unethical in other contexts, such as exaggerating or misrepresenting the evidence against the suspect (MAXIMISATION).

Fred Inbau & John Reid advise these 9 steps with a suspect who has already been identified as possibly-guilty by ordinary interviewing. The suspect should be kept in isolation until the interrogation begins, to increase their anxiety.

1. (direct positive confrontation) the suspect is told with “absolute certainty” he committed the offence and his reactions are observed;
2. (theme development) the suspect is offered “themes” (face-saving stories) that MINIMISE the implications of the crime so she can accept responsibility for it;
3. (handling denials) the interrogator must interrupt the suspect’s denials, since they give the suspect a psychological advantage
4. (overcoming objections) guilty suspects will move from denials to objections, explain why they couldn’t have committed the crime – these should be ignored;
5. (gaining the suspect’s attention) as objections fail, the suspect withdraws, so the interrogator retains attention by moving closer, making eye contact, using first name, etc.;
6. (handling the suspect’s passive mood) this new passive mood can be manipulated to make the suspect remorseful (if you can make them cry, they’re guilty!);
7. (presenting the Alternative) dramatically, the interrogator presents the suspect with two versions of the crime, one in which her actions are callous or shameful, the other more face-saving and sympathetic;
8. (oral confession) this self-incrimination is turned into a full-blown confession, with only the interrogator present;
9. (written confession) witnesses are called in for a more binding written confession.

The Reid Technique is an American procedure, created by Inbau and Reid in their book Criminal Interrogations & Confessions, which is still a how-to manual for many American police forces. Fred Inbau has always argued that we give suspects too many rights and that it’s justifiable for police to deceive, harass or use tricks to force a confession. He was a bitter opponents of the Miranda Rights introduced in the USA in 1966, which give a suspect the right to “take the 5th amendment” and say absolutely nothing during interrogation.

There’s no denying the effectiveness of this sort of technique, which is specially designed to create anxiety and doubt in the most hardened suspects and trick them into a confession. The interrogators maximize the severity of the crime, the weight of the evidence against the suspect and the severity of the punishment that a court will give out. Then they minimize the suspect’s personal involvement, inviting them to shift the guilt onto accomplices, bystanders or even the victim. The important stage is step 7, where the suspect agrees to a “socially acceptable” version of the crime, without realizing they are still pleading guilty.

In 1967 Philip Zimbardo reviewed American police training manuals and argued the techniques were coercive and an infringement of the suspect’s dignity and fundamental rights. Dr Barrie Irving, former-Director at the UK Police Foundation, agrees, suggesting that confession is a normal response to an oppressive situation, especially for first-time suspects, since it reduces the uncertainty caused by confinement (shame and loss of control), isolation and the threat of harm.  Irving compares this experience to Milgram’s ‘agentic state’. In the UK, the sort of deception or coercion involved in the Reid Technique is prohibited for police conducting interviews with criminals. 

The police are often worried about the danger of a FALSE NEGATIVE – letting a guilty suspect walk free. However, the public are often more concerned about a FALSE POSITIVE – identifying an innocent person as being guilty. Why do innocent people confess to crimes they haven’t committed?  Cases like the Birmingham Six and the Guildford Four have made this a high profile problem since the ‘90s.  Prof. Gisli Gudjonsson produced the Gudjonsson Suggestibility Scales (GSS), which are psychometric tests now used throughout the world when the issue of false confessions arises. Gudjonsson describes three types of false confession:

1. Voluntary: The innocent person confesses because they believe they are guilty (usually associated with mental disorders, eg. schizophrenia)
2. Coerced - internalised: The person is convinced by the police that they are guilty, although they are innocent (often linked to amnesia because of drugs or head injuries: the person relies on the police to fill in the gaps in their memories)
3. Coerced - compliant: The person confesses though they know they are innocent (usually because of coercive interrogation: the confession is a way out of the situation)

Gisli Gudjonsson & Jim McKeith (1990) carried out this case study into a 17-year-old man (referred to as “FC”) accused of two murders. In 1987, two elderly women were found battered to death in their home. Their savings had been stolen and there were signs of sexual assault. A few days later, FC was arrested. He had been questioned in connection with another case and there were inconsistencies in his account of his movements at the time of the attack. Also, he was spending more money than usual. This was, of course, circumstantial evidence – there was no forensic evidence (fingerprints, DNA, witnesses) linking FC to the crime.

FC was of average intelligence, suffered from no mental illness and his personality was not obviously abnormal. However, after his arrest he was not allowed access to a solicitor and was interviewed for 14 hours by the police with no one else present. He denied being near the scene but was repeatedly accused of lying. Many of the questions were leading and accusatory; in particular, FC was distressed at the police’s claims that he was sexually impotent! At the end of the interview, he confessed. The next day, in front of a solicitor, he retracted his statement but, after questioning about the failure of his relationships with women, he confessed again. There were three further interviews and later wrote a statement incriminating himself.

FC spent a year in gaol for the crimes, but then someone else pleaded guilty to the murders and FC was released. He was tested in prison by psychiatrists who found no sign of mental illnesses, but he did score 10 for suggestibility on the Gudjonsson Suggestibility Scales (abnormally suggestible). His IQ was 94 (fractionally below average) and on Eysenck’s Personality Inventory he came out as a stable extravert (a normal, healthy personality). Gudjonsson & MacKeith identify this as a case of “coerced compliant” false confession – FC caved in to the intense pressure of the interviews and confessed as a way of escaping from an intolerable situation. Interestingly, after his release FC’s self-confidence improved, as if his experiences had hardened him.

Gudjonsson argues there are four factors surrounding every confession that needed to be investigated to find out if a confession has been produced through coercion:

1. The Defendant: False confessions more likely from the very young, the very old, low IQs and sufferers from mental disorders (eg. depression, schizophrenia)
2. The Arrest: Suspects arrested suddenly, violently or in the middle of the night, or interrogated for long periods or at night, are more likely to make false confessions.
3. Mental/Physical state: Confessions are unreliable where suspect is stressed, anxious, ill or intoxicated
4. The Interrogation: Coercive, biased or leading interview tactics can encourage vulnerable suspects to make false confessions

Despite the introduction of PACE to regulate police interviewing, vulnerable suspects are still not routinely identified and allowed to have an ‘appropriate adult’ to help them.  For example, Gudjonsson notes that the four members of the Birmingham Six who did confess scored higher for suggestibility on the GSS than the two who asserted their innocence. Despite these cases, the legal system rarely acknowledges false confessions and police and judges are reluctant to accept evidence that a confession was false.

Watch this Google Video on the Birmingham Six - their own story.

Gudjonsson & MacKeith's case study is very revealing and raises a lot of questions about how the police go about their questioning of suspects. However, it is a study of just one suspect, so it’s difficult to generalise it to other cases or other police forces. FC did seem, to all intents and purposes, to be a normal (if slightly inadequate) young man who didn’t need any special considerations when being interviewed about a crime. His abnormally high suggestibility only came to light later. Some people argue that the police ought to screen suspects for high suggestibility before interviewing them, but then it would be very easy for genuinely guilty suspects to fake high suggestibility in order to get their convictions overturned.

You should link this research with the findings of Elizabeth Loftus on reconstructive memory. Loftus’ experiments show how fragile our memories are and how easily crucial details can be added or altered by forceful or leading questioning. Interest in false memories has become a major branch of cognitive psychology.