Profiling, Screening

Screening of all kinds plays an increasing role in everyday life. Luggage is screened by x rays at the airport to ensure it does not contain any dangerous items. People are screened for cancer to enable cases to be caught and treated early. Employees may be screened at random for the presence of alcohol or drugs. Psychological screening is carried out to ensure someone's suitability for a particular job. Screening is a useful way of a forensic psychologist gaining some basic knowledge of a suspect's mental and psychological characteristics before proceeding to more specialized testing and a full psychological profile . The tests used in screening are quick and simple. Sometimes they can even be done and assessed by computer. These tools differ from the psychology quizzes sometimes found in magazines in that they usually have been validated by years of research and experience so the results are meaningful. There are two basic types of psychological screening used in forensic investigation, personality and cognitive screening. Each type gives the psychologist a mini-profile of the suspect which can form a useful basis for more detailed and individual examination.

Personality screening often involves standardized tests such as the Minnesota Multiphasic Personality Inventory or the California Psychological Inventory. These are designed to measure key personality characteristics such as introversion or extroversion, intuition, honesty, neuroticism, optimism, and so on. The results may give the psychologist a feel for whether the person was likely to have committed the crime in question. In the forensic context, more specific screening tools, such as the Psychopathy Check List may also be used. Psychopathy, or anti-social personality disorder, is very common among criminals and a high score may be a useful pointer although not, in itself, proof of guilt. Another specialized screening tool is the Structured Interview of Reported Symptoms, which detects malingering (pretending to be still ill or injured).

Most people are used to taking personality tests in everyday life—after all, they are often used in recruitment so they have become a standard part of a job interview. In many kinds of work, such as teaching and law enforcement, there will be an emphasis on trying to discover the person's integrity and this is often a focus in a criminal investigation. People may think they can cheat a personality test but, in reality, the list of questions is designed to minimize this possibility because certain items are designed to spot untruthfulness and the test as a whole looks for consistency in the replies. Outright lying on the part of the suspect is also common during an investigation. That is why the forensic psychologist will always take the mini-profile alongside other evidence to form his or her conclusions. Thus, if the person does not want to seem like a loner in the belief that makes them look guilty of the crime, they may try to skew the answers on the personality test to make themselves look sociable. However, in an interview their true tendencies will emerge.

The other kind of basic screen which is done by the forensic psychologist is the cognitive test which profiles a person's mental ability. He or she may use a standard instrument such as the Wechsler Adult Intelligence Scale, which measures the intelligence quotient or IQ. On its own this is limited, as people have different kinds of intelligence. Someone who is good with numbers, for example, may have little verbal ability. Nevertheless, it is useful, because a person of very low intelligence is unlikely to have committed a sophisticated computer crime, for instance. They may, however, have carried out a violent attack. Other tests of cognitive ability such as memory, verbal reasoning, and comprehension can also help reveal whether the suspect was capable of the crime. Sometimes the crime scene will yield evidence of detailed planning. This may or may not match the mini mental profile the psychologist builds of the suspect. Again, most people encounter such tests on an everyday basis. In most jobs, the employer wants to know if the person has at least minimal mathematical ability and the ability to follow instructions.

The advantage of psychological screening tools is that they are standardized, validated, and therefore, accepted by the courts as part of the evidence. However, on their own they are limited. Just as recruitment for a top job cannot be done on testing alone, it must be followed up with one or more interviews, a criminal cannot be convicted by the use of a screening tool. Nevertheless, preliminary psychological screens play a very useful role in the assessment of suspects.

see also Psychological profile; Psychology.