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Forensic Psychology

Forensic psychology is literally court-related psychology. However, the term is usually applied to police work such as criminal investigation.

In the late 1990s, many students became interested in forensic psychology. Perhaps this was due to FBI profiler John Douglas's best-selling book.

There were also TV programs about profilers who were presented as pos­sessing uncanny psychic abilities. As we will see below, successful profiling depends more on computer skills than psychic abilities.

One student at our university who was interested in forensic psychology. However, she found no courses devoted to the topic.

The solution was to create a field experience course, an option available to psychology majors allowing individual placements in psychology-related settings outside of campus. This was available as an option if a professor agreed to sponsor the field experience course, staying in touch weekly with the student and a supervisor at the job site.

The student contacted people at the Atlanta city jail, close to where she grew up, and she received approval to serve as a volunteer there during the summer while she was living back home. She was required to keep a daily journal about her experiences, and she re­ceived academic credit for her volun­teer work through the Field Experience course number.

The student was as prepared as she could be, using our curriculum in psych­ology. She was between her third and fourth year and had taken courses like Abnormal Psych­ology, Social Psych­ology, and Behavior Modification. All of these proved to be relevant to her summer field experience, she said.

What was the undergraduate student allowed to do?

During the summer, the student did intake interviews (collecting information from prisoners when they arrived), talked to prisoners in their cells when they needed a good listener, and ran errands for the professional staff.

Of course, she could not make important decisions or administer psychological tests. Those respons­ibilities had to be performed by a licensed psychologist. However, the student's work was appreciated. She was offered a job when her field experience course ended.

The everyday activities of a real-world forensic psychologist usually involve testing, talking, and counseling, not coming up with a psychological profile of a serial killer. However, the "profiler" stereotype does have its real-world counterparts.


In the 1950s, a series of bombs explod­ed in the Garment District of New York City. Neatly-penned notes arrived at police headquarters, claiming respon­sibility. After studying the notes, psychiatrist James Brussel was able to provide police with a detailed description of the bomber.

How did Brussel describe the "mad bomber"?

"He goes out of his way to seem perfectly proper, a regular man. He may attend church regularly. He wears no ornament, no jewelry, no flashy ties or clothes. He is quiet, polite, methodical, prompt...

"Education: at least two years of high school. The letters seem to show that. They also suggest that he's foreign-born or living in some community of the foreign-born... He is a Slav...

"One more thing," I said, my eyes closed tight. "When you catch him–and I have no doubt you will–he'll be wearing a double-breasted suit....And it will be buttoned," I said. (Brussel, 1968)

You can sense the embellished quality of this tale from the added details like "my eyes closed tight" but let us take it at face value. Brussel had reasons for most of his assumptions.

He assumed the bomber would be a middle-aged man because paranoia most often afflicts middle-aged males. Brussel assumed the man was "exact, precise, neat, clean" because the letters in the notes from the Mad Bomber were printed neatly and metic­ulously, with no errors, erasures, or crossed out words.

The Mad Bomber's peculiar use of English suggested to Brussel that he was foreign-born. The Mad Bomber referred repeatedly to "the Con Edison" in his notes. "New Yorkers had been calling it just plain Con Ed for decades."

How did Brussel come up with his description?

Similar clues led Brussel to other predictions. When Brussel solved the case (the late 1940s) a very neat man was likely to be wearing a double-breasted suit in public. Peculiarities in the man's use of English reminded Brussel of the Slavic languages.

Computers did not exist when Brussel made his predictions. Within a few decades they were scanning large amounts of data to provide invest­igators with useful profiles of criminals.

As noted in Chapter 1, correlations enable predictions. To make a profile, a researcher asks a computer to look for correlations: what are traits of criminals convicted of this type of crime in the past.

The results can oddly specific. An example comes from a case in Georgia, reported in The Atlanta Constitution:

There was the case of a 12 year old girl found murdered near her Adairsville, Ga., home in December 1979. The murderer had sexually assaulted her and crushed her head with a large rock.

The local authorities called the FBI for help in locating a suspect. John Douglas, a psychologist with the FBI Behavioral Science Unit, told them to look for a man with the following characteristics:

–He would be a divorced white male.

–He would be in his mid-20s.

–He would drive a black or blue car.

–He would have a "macho" laborer's job.

–He would have had some prior contact with the victim.

–He would be a high school drop-out.

–He would have served in the Army or Marines, probably with a medical or dishonorable discharge after less than six months.

–He would have a prior record of sex crimes.

–He would pass a lie detector test, showing no deception.

Douglas recalls, "They told me, 'You just described a guy we released as a suspect in the case,'" Douglas gave them some tips on how to interview the man, Darrel Gene Devier, who later confessed to the FBI and received a death sentence.

–Devier was a divorced white male.

–He was 24 years old at the time of the killing.

–He drove a dark blue Pinto.

–He worked as a tree-limb cutter.

–He had worked near the driveway of the victim before the killing, making sexual remarks to her.

–He was an eighth-grade drop-out.

–He received a general discharge from the Army after less than a year in the service.

–He had been accused of attempting to rape a 13-year-old girl in a previous incident.

–He showed no deception on a lie detector exam­ination. (Post, 1982)

How does the computer do it? The com­puter finds correlations: statistical patterns or trends in the data from past crimes. Over years of feeding crime information into a database, a huge amount of information is stored, and a computer can search that data quickly.

How does the computer do it?

In this case, past crime descriptions provided the information that (for exam­ple) a person who commits a brutal murder is likely to be driving a dark-colored car. That is an insight that would not necessarily occur to a human.

As noted in Chapter 1, we do not need to know the cause of a correlation to use it for prediction. We only need for the correlation to last into the future. In this case it did, because Devier was driving a dark blue car.

As for why it was predictable that Devier would pass a lie detector test, you may have that figured that out. The psycho­path, the type of person most likely to commit a brutal crime like this, feels no guilt and has a very non-reactive nervous system (insensitive to electric shock, for example). They easily pass lie detector tests.


Brussel, J. A. (1968) Casebook of a Crime Psychiatrist. New York: Grove Press.

Post, H. (1982, April 11) FBI supersleuth had a big role in Williams trial. Atlanta Constitution, pp.1A,14A.

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