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Leonard Mlodinow

Leonard Mlodinow

The Illusions of Memory

The modern view of how human memory works—and doesn't.

The traditional view of memory, and the one that persists among most of us, is that it is something like a storehouse of movies on a computer’s hard drive. This is a false concept of memory, analogous to the simple video camera model of vision, which is also wrong—see my blog entry “Our Unconscious and Social Reality.”

In the traditional view, your brain records an accurate and complete record of events, and if you have trouble remembering, it is because you can’t find the right movie file (or don’t really want to), or because the hard drive has been corrupted in some way. If memories were indeed like what a camera records, they could be forgotten, or they could fade so that they are no longer clear and vivid. But it would be difficult to explain how people could have memories that are both clear and vivid while also being wrong. Yet that happens, and it is not infrequent.

It’s rare to have proof of what actually happened, so in most cases we never know how inaccurate our memories really are. However, this is the fortieth anniversary of one case in which those who study memory distortion were provided with both a record of someone’s memory, and of what really happened, records that couldn’t have been surpassed had the scientists orchestrated the incident themselves. I’m referring to the Watergate scandal in the 1970s.

The Watergate scandal concerned a break-in by Republican operatives at the headquarters of the Democratic National committee, and the subsequent cover-up by the administration of President Richard Nixon. A fellow named John Dean, White House Counsel to Nixon, was deeply involved in orchestrating the cover-up, which eventually led to Nixon’s resignation. Dean was said to have an extraordinary memory, and, as millions around the world watched on live television, he testified at hearings held by the United States Senate.

In his testimony, Dean recalled incriminating conversations with Nixon and other principals in such great detail that he became known as the “human tape recorder”. What endows Dean’s testimony with scientific importance is the fact that the Senate Committee later discovered that there was also a real tape recorder listening in on the President: Nixon was secretly recording his conversations for his own later use. The human tape recorder could be checked against reality.

Psychologist Ulric Neisser did the checking. He painstakingly compared Dean’s testimony to the actual transcripts, and catalogued his findings. John Dean, it turns out, was more like a historical novelist than a tape recorder. He was almost never right in his recollections of the content of the conversations, and he was usually not even close.

Late that afternoon I received a call requesting me to come to the President’s Oval office. When I arrived at the Oval Office I found Haldeman [Nixon’s Chief of Staff] and the President. The President asked me to sit down. Both men appeared to be in very good spirits and my reception was very warm and cordial. The President then told me that Bob—referring to Haldeman—had kept him posted on my handling of the Watergate case. The President told me I had done a good job and he appreciated how difficult a task it had been and the President was pleased that the case had stopped with Liddy. I responded that I could not take credit because others had done much more difficult things than I had done. As the President discussed the present status of the situation I told him that all I had been able to do was to contain the case and assist in keeping it out of the White House. I also told him there was a long way to go before this matter would end and that I certainly could make no assurances that the day would not come when this matter would start to unravel.

On comparing this meticulous account of the meeting to the transcript, Neisser found that hardly a word of it was true. Nixon didn’t make any of the statements Dean attributed to him. He didn’t ask Dean to sit down; he didn’t say that Haldeman had kept him posted; he didn’t say that Dean had done a good job; and he didn’t say anything about Liddy or the indictments. Nor did Dean say any of the things he attributed to himself. In fact, not only did Dean not say that he “could make no assurances” that the matter wouldn’t start to unravel, he actually said pretty much the opposite, reassuring Nixon that “Nothing is going to come crashing down.” Of course, Dean’s testimony sounds self-serving, and he might have been intentionally lying about his role. But if he was lying, he did a poor job of it, because, on the whole, his Senate testimony is just as self-incriminating as the actual, though very different, conversations revealed by the transcripts. And in any case, what is most interesting are the little details, neither incriminating nor exonerating, about which Dean seemed so certain, and was so wrong.

Today psychologists recognize that while people have a good memory for the general gist of events, we have a bad one for the details. Moreover, when pressed for the unremembered details, even well-intentioned people making a sincere effort to be accurate will inadvertently and unconsciously fill in the details by making things up, employing their expectations, desires, prior knowledge and beliefs. And finally, people will believe the memories they make up. And so although we can’t go through life taking notes, we can, and should, be aware that the details of scenes and incidents we remember, though they seem real, are often biased.

Adapted from Subliminal: how your unconscious mind rules your behavior Copyright 2012 by Leonard Mlodinow