Forensic Psychology For Dummies (9 page)

Mens rea
– meaning that the individual knew what he was doing, knew that it was wrong and did it intentionally.

In their wisdom, lawyers think of mental disturbances as (simplistically) implying that the person isn’t guilty if his mind isn’t guilty. (They have a neat Latin phrase for this, but I think you’ve had enough Latin for now!) When lawyers start talking about the mind, though, they open the door to psychologists and psychiatrists, who are more than ready to comment on other people’s minds and how in contact with reality they are.

Now, back to the McNaughton case. At the time, convicting someone who didn’t appreciate the significance of his own actions, or whose actions weren’t under his rational voluntary control, was considered uncivilised. The confusion in the existing law that required only the second condition of
mens rea
to be met, but didn’t detail how that can relate to mental disturbance, led to a clarification of the law in what became called the McNaughton Rules. The rules recognised that a ‘disease of the mind’ can exist in which the person couldn’t have voluntary and conscious control over his actions or be really aware of their significance. Therefore, on the basis of
mens rea
, McNaughton was found not guilty of murder.

The idea that the mind (rather than the brain) is an organ that can be diseased, like the liver or heart, shows how subtle (or possibly ignorant!) lawyers can be. Plenty of illnesses of the brain don’t affect a person’s ability to voluntarily and consciously commit a crime. Similarly, many disturbed mental states can’t be linked directly to brain disease. So a seemingly straightforward legal requirement opened the doors to professionals who worked with mentally ill patients to give guidance to the court on whether the defendant was in a psychologically sound state at the time of the crime to be legally responsible for his actions. This situation is still a central issue on which psychologists and psychiatrists give guidance to the court.

Another case, this time from the US, helps to illustrate this situation of clinical psychology helping the legal system. When Christopher Simmons was a few months shy of his 18th birthday, he carefully planned and carried out the murder of Shirley Crook. Simmons was given a death sentence when convicted. However, the American Psychological Association supported his appeal against the death sentence by reviewing studies of teenagers. They stated that juveniles under the age of 18 didn’t have the mental ability to take full moral responsibility for their actions, and therefore couldn’t be regarded as having
mens rea.
The US Supreme Court accepted this advice and overturned the death penalty. (Turn to Chapter 16 for more on crime and juveniles.)

The consideration of the mental state of the defendant has produced many other issues on which the court welcomes guidance, including:

Deciding whether, due to intellectual ability or mental state, the defendant can understand the court procedures well enough to be fit to plead.

Determining the ability of children to be witnesses and the most effective procedures for involving them in court cases (see Chapter 4).

Predicting the likely risk that an offender may pose in the future and hence implications for his sentencing.

Deciding whether an offender’s mental condition is likely to be responsive to treatment.

Helping with the support and assistance to victims (I look at this in Chapter 7).

Examining the Building Blocks of Forensic Psychology

Academic and clinical approaches to psychology may differ. For example, academics research more general aspects of human psychology, such as perception, personality or memory while clinicians are concerned with examining the thoughts, feelings and actions of their patient in the clinic. However, for the forensic psychologist, the academic and clinical strands have never been totally distinct. Nowadays the two strands overlap in many different ways. This raises the interesting question of how forensic psychologists know what they know.

The chief difference between the layman and the professional is that the professional can draw on the body of objective knowledge and findings that come from established scientific procedures. Therefore in this section, I look at the basis on which forensic psychologists form an opinion. Having some knowledge of how this process works, helps to give you a clearer picture of the nature of forensic psychology.

Experimenting

Imagine that you want to show that a particular procedure such as detecting lying really works. The most reliable way of doing this is by using the long-established scientific procedure of the carefully controlled experiment. This experiment needs to demonstrate that the procedure detects when people are lying better than the chance probability of, say, throwing a dice, and also that the scientific procedure can detect the truth better than chance.

The challenge in setting up these types of experiments is that ethical limits often exist on what the subjects in an experiment can be asked to do. For example, you can’t ask people to commit a real crime, mix them in with others who didn’t and then see if you can spot the liars. You have to set up some sort of artificial situation, which means that, no matter how realistic you make it, the same emotional pressures don’t exist as, for example, in a real murder case where the murderer is desperately trying to avoid being found out.

Other difficulties come from getting a reliable comparison between the conditions that are of interest and some neutral comparable circumstances. An important example is in experiments that are trying to improve interview procedures. What do you compare any new interview procedure with? How do you measure the differences between new and comparison procedures? As in the example of lying, interviewing people about a serious event you know is fictitious can be fruitless, but if you interview people about actual events there may be something special about those events and how they’re remembered that means they aren’t typical of other situations. Does it make any difference whether you’re interviewing people who have experienced a burglary in contrast to a violent assault?

These questions show how complicated setting up carefully controlled experiments in the area of forensic psychology can be.