Forensic Psychology For Dummies (47 page)
Read Forensic Psychology For Dummies Online
Authors: David Canter
Are there spontaneous corrections?
This list of questions isn’t without its critics and certainly isn’t foolproof. It doesn’t, for example, show the difference between a partially truthful account from an untruthful one, especially if the untruthful version is built upon something that actually happened, but not to the suspect or witness or not at the time claimed. As I discuss in Chapter 4, memory fades quickly over time and so the lack of clarity in what a liar says can be mistaken for a sign that he’s telling the truth. Plus, memories of a traumatic event can leave an indelible mark and can be much sharper than the answers to these questions may lead you to expect.
Don’t do that, do this!
Aldert Vrij and his colleagues have been looking into ways of exploiting the intellectual demands made on a person when inventing and maintaining a lie. Vrij claims that if you ask a suspect to carry out two separate tasks at the same time, putting pressure on his thought processes, more signs of lying become apparent – for example, asking the suspect to play a computer game while making his statement, or giving an account of what happened in reverse chronological order. By putting on this additional pressure many of the weaknesses in the plausibility of what is being said can come to the surface.
Looking at legal approaches
For the forensic psychologist the most common way of finding out the truth of a suspect’s statement and detecting deception is during the court proceedings. Courts rely heavily on their own tried and tested approaches to getting at the truth, despite research showing the many difficulties associated with detecting lying and deceit.
Power of court proceedings
Lawyers have great confidence in the ritual of the court as the best way of extracting the truth from the person standing in the witness box. The witness or defendant has to swear an oath and is then examined closely in front of the judge, jury (if one is present), members of the public and sometimes even victims. This confidence comes partly from the belief that if a ritual is powerful enough, a person feels compelled to tell the truth. Indeed, the swearing of an oath comes from times in which a belief in God’s wrath was so strong that a person feared divine punishment if he lied under that oath.
Getting to the truth in a court of law relies on the effectiveness of the questioning of witnesses and the defendant. In many jurisdictions, the defendant may not be open to questioning, which was the case in British courts until quite recently, because of the belief that a defendant can’t be expected to be telling the truth.
In the US the view that a person is never put in a position where he can incriminate himself is enshrined in the Fifth Amendment to the US Constitution: ‘nor shall be compelled in any criminal case to be a witness against himself’.
Plausibility
The court proceeding puts a great deal of emphasis on the plausibility of a person’s statement. To establish the truth of a statement the court has to refer to what’s generally expected to be possible or typical for a person’s lifestyle or set of circumstances. Forensic psychologists therefore look at statements in terms of what the person may be expected to know and how ready the person is in giving that information, including: