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Psychology in Court

What is it like to be a psychologist serv­ing as an expert witness in court? Kick­ing off the inaugural issue of The Journal of Forensic Psychology, Haward (1969) wrote:

In some ways, court work offers a more exciting challenge to the psychologist than any other role he takes up. Nowhere else are his findings exposed to such merciless criticism or his beliefs taxed to their utmost credulity. (in Brodsky, 1973)

Such consulting work, in which a psych­ologist offers an expert opinion to back up one side or the other of a legal case, can be very profitable. There is no problem motivating psychologists to face the criticism and heavy professional responsibilities of court­room work. It is true, however, that a psychologist offering expert opinions in a courtroom can expect to be challenged in every way.

What must an expert witness expect to experience?

Patrick Carnes, the expert on sexual addiction described earlier in this chapter, was verbally attacked when he testified about President Clinton. The defense lawyer pointed out that Carnes "only" had a doctoral degree in education, not in psychology.

The fact that Carnes had written several books on sexual addiction and was considered a leading authority on the subject was ignored by the defense attorneys. The defense tactic, chal­lenging Carnes's credentials, is a variation of the source degradation strategy mentioned in Chapter 15.

Source degradation is a tactic for reducing the persuasive power of an argument by attacking the credibility of the source. A psychologist testifying in court must expect this type of attack from the other side, which will try to "degrade" the credibility of the psych­ologist's message by questioning his or her credentials or qualifications.

Psychologists are sometimes called upon to do research involving memory or perception, to back up or contradict a courtroom argument. This happened in the case of Processed Plastic v. Warner Communications (1982).

How did social scientists help in a suit about a toy plastic car?

Warner Communications owned The Dukes of Hazzard television series. They allowed several toy companies to produce replicas of a car (the General Lee) used by the heroes of the series.

The Processed Plastic Company was not one of those companies, but it began to sell a toy car that looked like the General Lee. In court, Warner produced a survey of children questioned in random groups at shopping malls.

The researchers showed that 82% of the children shown a Processed Plastic car identified it as "the Dukes of Hazzard car." The trial court decided, and an appellate court agreed, these findings showed Processed Plastic had infringed on Warner's trademark rights by creating consumer confusion (Monahan & Walker, 1988).

How did a psychologist help two men who confessed to a burglary?

Arens and Meadow (1956) reported a case in which two men signed a prepared confession statement after arrest for a burglary. Later, both men claimed they were innocent and said they had signed the confession only after being threatened by police.

A psychologist analyzed the confession and compared it to other samples of writing from the two defendants. The confession was not in their own lan­guage. The vocabulary and sentence construction was entirely different from what the men would normally use.

After a psychologist testified about this, the court threw it the confession, not allowing it to be used in court. The judge ruled that it showed "evidence of fabrication or fraudulent alteration by outsiders" (Arens and Meadow, 1956).

Eyewitness Identification

Psychologists have known for years that eyewitness reports can be full of errors. In an early classic, On the Witness Stand (1908), Hugo Munsterberg told how a famous criminologist in Berlin–Professor Lizst–arranged for a fake murder in one of his classes.

The Professor had spoken about a book. One of the older students suddenly shouts, "I wanted to throw light on the matter from the stand­point of Christian morality!" Another student throws in, "I cannot stand that!"

The first starts up, exclaiming, "You have insulted me!" The second clenches his fist and cries, "If you say another word..." The first draws a revolver. The second rushes madly upon him.

The Professor steps between them and, as he grasps the man's arm, the revolver goes off. General uproar. In that moment Professor Lizst secures order and asks a part of the students to write an exact account of all that has happened.

The whole had been a comedy, carefully planned and rehearsed by the three actors for the purpose of studying the exactitude of observation and recollection. (Munsterberg, 1908, pp. 49-50)

What was Professor Lizst's demonstration?

To analyze the results, the performance was "cut up into fourteen little parts which referred partly to actions, partly to words" and this was matched to the written memories of student witnesses. The smallest number of mistakes reported by any student was 26%; the largest was 80%. People forgot elements, added elements, and remembered things incorrectly.

What sorts of mistakes did eyewitnesses make?

Words were put into the mouths of men who had been silent spectators during the whole short episode; actions were attributed to the chief participants of which not the slightest trace existed; and essential parts of the tragi-comedy were completely eliminated from the memory of a number of witnesses. (Munsterberg, 1908, p.51)

Word of the experiment spread, and other teachers tried similar demon­strations. It became "the fashion and almost a sport" according to Munster­berg. He added that such experiments "will still have to be continued with a great variety of conditions if the psychological laws involved are really to be cleared up" (Munsterberg, 1908, pp. 53-54).

What are some findings about eyewitness identification from Loftus?

One psychologist who did such research in a great variety of conditions is Eliza­beth Loftus. She researched the issue of eyewitness identification from the 1970s through the 1990s (e.g. Loftus, 1975).

Loftus was called to testify about this on hundreds of occasions. She cited case histories and experimental studies to demonstrate that eyewitness accounts could be inaccurate or completely fabricated.

Human memory is easily misled by leading questions despite the best efforts of witnesses to remember accurately. False memories are easily created simply by asking repeated questions about an event that never occurred. Witnesses may be confident about the memories despite their artificiality (Loftus, 1997).

What happened to psychologist Donald M. Thomson?

A false identification may also be based on a false memory constructed out of different experiences which are forgotten. An example involved Donald M. Thomson, a prominent experimental psychologist and memory researcher. Bower (1990) related the story.

Donald M. Thomson, an Australian psychologist and lawyer, undoubted­ly will never forget the day 15 years ago when he walked into a Sydney police station on routine court-related business and was arrested for assault and rape in a weird turn of events worthy of an Alfred Hitch­cock movie.

The evening before his arrest, Thomson appeared on a local tele­vision program, where he discussed psychological research on eyewit­ness testimony and how people might best remember the faces of criminals observed during a robbery. As he spoke, a Sydney woman watching the show was attacked, raped and left unconscious in her apartment. When she awoke several hours later, she called the police and named Thomson as her assailant.

The following day, after Thomson's arrest, the woman confidently selected him as the perpetrator from a lineup of possible rapists at the police station.

Thomson, of course, professed his innocence. "The police didn't believe me at first," he recalls, but I had appeared on a live television show when the crime occurred, so I had a good alibi."

Officials quickly dropped the charges when they realized the woman had unwittingly substituted Thomson's televised face for that of the attacker. "She had apparently watched my television appearance very closely, but it's not clear if she ever saw her assailant's face," said Thomson.

What is cryptomnesia?

When a person recollects something and inserts it into a current thought or memory, without realizing it is from a different source, this is called cryptom­nesia. Cryptomnesia is a false memory (or sudden insight) based on an earlier experience which is itself forgotten.

For example, a friend may tell you something with great excitement, for­getting that you were the one who supplied this information in the first place. If your friend insisted he or she "thought it up by myself" or "saw it on TV" when you knew the information came from yourself, that would be cryptomnesia (assuming you are correct).

To the person who constructs a false memory, it feels perfectly normal and believable. Of course, Thomson's case was particularly strange because Thom­son was talking about problems with eyewitness identification when he appeared on TV.

His TV appearance apparently planted his facial appearance in the memory of the woman. She transferred the memory of his face onto the missing face of the rapist. To the women it felt like a mem­ory formed at the time of the attack.

Such a case is very important, because it shows in uncommon detail how false testimony can be generated. It does not happen through intentional dishonesty, but through creative synthesis of a memory in the brain.

A key factor in changing attitudes about eyewitness testimony is the emergence of DNA evidence. It is unusually precise and exact. In many cases, especially rape, there is physical evidence from a crime scene that preserves a criminal's DNA. Biological samples can be re-tested many years later.

What has been a "key factor" in changing attitudes about eyewitness testimony?

In case after case, prisoners have been released after serving years of a sentence, after DNA analysis showed they were wrongly convicted. According to Barry Scheck of the Innocence Project, 75% of the wrongful convictions over­turned by DNA evidence (over 300) were due to eyewitness testimony. For example:

Ronald Cotton was 22 in 1984 when he was picked out of a police lineup by a Burlington, N.C. woman who identified him as her rapist. He served 11 years in prison before DNA analysis of evidence showed he was innocent.

Cornelius Dupree was convicted of rape and robbery in 1979 and served 30 years in prison. He twice rejected offers of parole because they would have required him to admit guilt, and he insisted he was innocent. He was exonerated by DNA and released from prison in 2009.

Bernard Webster was 19 when he was convicted in 1982 of assault and rape. A 47-year-old teacher identified him as the rapist. He was released in 2002 when DNA evidence showed he was innocent and implicated a different man who had previously contributed DNA when arrested.

There are many more similar cases, and an alarming number of them show the same pattern: black men identified by white women who were victims of rape. Psychologists say police station lineups (in which the accused is put in a line with several other people) were used in many of these cases.

Police sometimes use identi-kits consist­ing of assortment of facial features that can be assembled into a face, to help rape victims remember the face of their attacker. This only makes things worse, researchers say, because identikits cannot match a criminal's face exactly, and they introduce false elements into memory.

Because of these cases, most states in the U.S. now allow prisoners to petition for re-examination of physical evidence using DNA techniques. Spokesmen for the Innocence Project say they have received over 10,000 requests for invest­igation. Only 1% can be accepted, and half of those are thrown out because the evidence no longer exists.


Arens, R. & Meadow, A. (1956, January). Psycholinguistics and the confession Dilemma. Columbia Law Review, 56, 19-46.

Bower, G. H. (1990). Awareness, the unconscious, and repression: An experimental psychologist's perspective. In J. Singer (Ed.), Repression and Dissociation: Implications for Personality, Theory, Psychopathology, and Health (pp. 209-231). Chicago: University of Chicago Press.

Brodsky, S. L. (1973). Psychologists in the Criminal Justice System. Urbana, IL: University of Illinois Press.

Haward, L. R. C. (1969) The role of the psychologist in English criminal law. Journal of Forensic Psychology, 1, 11-22.

Loftus, E. F. (1975). Leading questions and eyewitness reports. Cognitive Psychology, 7, 560-572.

Loftus, E. F. (1997, March) Creating false memories. Scientific American, 277, 70-75.

Monahan, J. & Walker, L. (1988). Social science in law: A new paradigm. American Psychologist, 43, 465-472.

Munsterberg, H. (1908). On the Witness Stand: Essays on Psychology and Crime. New York: Doubleday.

Write to Dr. Dewey at

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