According to Hyman (1989) deception implies that an agent acts or speaks so as to induce a false belief in a target or victim. Deception can occur in everyday life. Whether it is telling someone they look nice or not telling them that they look fat. This is an important process for forming relationships and general social interaction. However, although this is useful for social interaction, it is a serious problem in other areas. Deception can be a problem when people actively deceive in job applications, giving evidence and in court.
Being able to detect whether a person is lying or not in a criminal situation in very relevant for the legal system to work effectively. Many people claim to be able to tell whether someone is lying or not by particular signs. However research shows that this may not be the case. In the earliest research into deception, Eckman (1969) suggested that deception could be detected by leakage cues. It was suggested that when these ‘micro-expressions’ occur, the person reveals their true feelings. Further studies looked into verbal and non verbal cues.
Some examples of verbal cues include higher pitch voice, speech hesitations and taking longer to answer questions. Some examples of non-verbal cues include twitching, pupil dilation, avoiding eye contact and increased sweating. However, Ekman (1974) later stated that no body movement, facial expression or voice change is an indisputable sign of deceit. However many people that are trained in lie detection are still taught to use these methods to detect deception. So how good are people at lie-detection?
Some studies show that the people who one would expect to be good at lie detection are fairly accurate (eg. Police officers). A recent study by Mann, Vrij and Bull (2004) showed that when shown videotapes of real-life lies and truths and found that the officers had an accuracy of 65%. This was found to be better than lab studies using, normal (non-trained) participants. Additionally, accuracy was negatively correlated with popular stereotypical cues such as gaze aversion and fidgeting. However, although this suggests that human lie detection is fairly accurate, earlier research has found the opposite.
According to Wallace (1999), psychological research on deception shows that most of us are poor judges of truthfulness. One may assume that this only applies to only ordinary people and not professionals. However further research shows that ‘this applies to professionals such as police and custom inspectors, whose jobs are supposed to include some expertise at lie detection’ (Wallace, 1999). An early study by Kraut and Poe (1980) that custom inspectors showed accuracy scores rarely exceed 65% where 50% is the chance level.
A later study by Kohnken (1987) showed that police officers performed no better than chance when judging the truthfulness of witness statements (on video). Furthermore, it was found that the more confident the officer was of their judgement, the more likely they were wrong. This suggests two things; 1) that there is no future in human lie detection, and 2) that the people are trained in lie dectectionmay not be any better than the ‘Average Joe’. However, later research shows that some people may genuinely be good at lie detection.
Ekman and O’Sullivan (1991) asked around 500 people from various legal areas (including Secret Service Agents, federal polygraphers, robbery investigators, judges and psychiatrists) to watch 10 60-second video clips of female nurses describing pleasant nature films they were supposedly watching as the spoke. However, half of the nurses were actually watching gruesome medical films. The findings showed that most of the observers detected deception at around the chance level. However, the Secret Service group had an 80% success rate. This seemed to suggest that there are people that are genuinely good at detecting lies.
In a further ongoing study to find these ‘wizards of detection’, O’Sullivan (in press) found that out of 13, 000 people investigated 31 were ‘true wizards’. When talking about her latest upcoming study at an American Medical Association’s 23rd Annual Science Reporters Conference in Washington D. C. , O’Sullivan remarked that these people have helped them to train others in deception detection. Furthermore it was stated that with 20 minutes of training, it has been possible to significantly improve someone’s ability to recognize ‘micro-expressions’ which are involved in many kinds of lies.
Therefore, although there is still only a relatively low amount of people who can accurately detect deception, if techniques can be learnt, the future for human deception detectors looks promising. However, at present it seems that these people are so few, that human lie detection, as an accurate source of lie detection, is still a few years ahead. Perhaps non-human alternatives that are already in place should be looked at for the future of lie detection. In the United States, the police services often use a lie detector called a polygraph.
It often assumed that lying is accompanied by a change in the body’s physiological activity (Bull, 1988). According to Raskin (1988), ‘the polygraph is a means of detecting biological traces of an event which is stored in the brain or a perpetrator or witness’ (p78). The polygraph is used by law enforcement agencies in the U. S. , the U. S. government and the private sector (e. g. to see if a partner is being faithful or not). It was developed by Leonarde Keeler in the 1930s to late ’40s. The device measures cardiovascular activity, elector dermal activity and respiratory activity.
The responses are recorded on a paper/needle trace and a trained expert analyses the readings. The expert asks the subject a few control questions and then questions that the subject will have to respond with a ‘yes’ or ‘no’ to. The expert compares patterns with those when the subject was definitely telling the truth. The expert looks for a number of things when detecting a lie. Firstly, it is expected that there will be an increase in breathing rate and heart rate. The cardiovascular responses are measured through a cuff on the arm which measures heart rate and BP.
When these increase it is thought that the subject is under stress and is lying. In addition, galvanic skin responses and breathing rates are monitored for changes that alert the examiner to stress (lying). The standard method in police situation is to administer a Controlled Question Test (CQT). This is a comparison method where the control question is a neutral or non-threatening question. This is followed by a relevant question and the comparisons are monitored. The use of the polygraph is common in the US; accuracy is generally thought to range from 85 to 90 per cent (Raskin, 1988).
However there are many problems with the system studies show it is not infallible. Firstly, it has been found by many studies that although the CQT is fairly accurate at detecting deception it cannot detect truthfulness in an innocent person better than chance (Kleinmuntz ; Szucho, 1984b). This suggests that the odds may be stacked again the innocent person. Additionally there may problems with the people who actually analyse the information. An earlier study by Szucho and Kleinmuntz (1981) showed that the best interpreter classified 18% of truthful subjects as untruthful.
The worst interpreter incorrectly classified 55% of truthful subjects as untruthful. This has serious implications as it provides further evidence that innocent people may be convicted of crimes they did not commit. Research has shown that the rate of false positive scores is consistently higher than of false negative results and overall accuracy of the polygraph falls to 80-90% at best. Additionally, according to Faigman, Fienberg and Stern (2003), over-confidence in polygraph accuracy may lead to jurors believing it as scientific fact if admitted as evidence.
Fortunately the US courts do not have to allow polygraph results to be admitted as evidence. However one occasion when it was admitted showed a further problem with this deception detector. A convicted criminal called Floyd ‘Buzz’ Fay was wrongly convicted using the polygraph on the basis of a failed polygraph and subsequently trained fellow inmates to cheat the tool. After only 20 minutes of instruction, 23 of the 27 inmates were successful in defeating the polygraph examination (Ford, 1995; Kleinmuntz ; Szucko, 1984). These ‘countermeasures’ present a real problem in that when someone is trained the device becomes useless.
Although some polygraphers claim to know about these countermeasures and compensate for them, a study conducted by Honts, Rakin and Kircher (1994), revealed that 50% of the subjects trained to fool an examiner succeeded. Therefore although the polygraph can elicit detection of deception, on it’s own it is not infallible. Additionally, the base rate for deception may also affect the accuracy of the polygraph. This refers to the fact that the polygraph assumes that there is at least some people who are guilty (e. g. 1 in 1000). This means that some people may be falsely accused, as it is assumed someone is guilty.
Furthermore, the environmental stress that the procedure elicits on the subject may evoke a natural response of stress rather than the occurrence of lying. In one such instance in 1982, a man who was expected to be executed the following day was given a polygraph test. Roger Coleman maintained his innocence when he asked for a polygraph test; the state claimed that he failed it. However there was strong evidence to suggest that he was innocent. The polygraph is most effective when it is assumed to work and the subject confesses. However as reported in a recent review of polygraph deception detection (Bull et.
al, 2004), the problem with confessions is that they are not independent from polygraph scores. In other words when the subject has already confessed the administering of a polygraph will obviously show that they are not lying because they have already admitted to the crime. This leads to a higher accuracy rating of the polygraph than is perhaps realistic. Although the polygraph is useful in gaining confessions from people who are genuinely guilty, the accuracy issues seem to suggest that perhaps it should not be used strictly for finding who is guilty of crimes.