Eyewitness Identification

Psychologists have known for years that eyewitness reports are often 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.

What have legal experts "known for years" about eyewitness identification?

What was Professor Lizst's demonstration?

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)

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 many 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). She was called to testify about it on hundreds of occasions. She cites case histories and experimental studies to demonstrate that eyewitness accounts can be inaccurate or completely fabricated, and that memories are 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 which never occurred, and witnesses may be confident in reporting such 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 may themselves be forgotten. An example involved Donald M. Thomson, a prominent experimental psychologist and memory researcher. Bower (1990) relates 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," says Thomson, now at Monash University in Clayton, Australia.

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 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 passed on 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 cryptomnsesia (assuming you were correct).

To the person who constructs a false memory, the recollection feels perfectly normal and believable. Of course, what makes Thomson's example particularly bizarre is that Thomson was talking about problems with eyewitness identification when he appeared on TV. His TV appearance planted his facial appearance in the memory of the woman. From there his face was transplanted 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 actually very important, because it shows in uncommon detail how false testimony can be generated, not through intentional dishonesty, but through creative synthesis of a memory in the brain.


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Copyright © 2007 Russ Dewey