Monday, January 01, 2001

Sins and Super Power on Memory Lane

The Seven Sins of Memory

By: Richard RestakM.D.


A super power memory would be on many people’s wish list for personal brain improvements. But before looking at some recent programs that promise help in achieving that goal and examining Daniel Schacter’s new book, we may well heed the musical dialogue between two legendary movie stars, the experience of an obscure Russian journalist, and the sad end of a major league baseball player, whose memory of one crucial play in one game of his career cost him his life. 

In the now classic 1958 musical Gigi, actors Maurice Chevalier and Hermione Gingold recall their final date:

Chevalier: I can remember everything, as if it were yesterday. We met at nine.

Gingold: We met at eight.

Chevalier: I was on time

Gingold: No, you were late

Chevalier: Ah, yes, I remember it well. We dined with friends.

Gingold: We dined alone.

Chavalier: A tenor sang.

Gingold: A baritone.

Chavalier: Ah, yes, I remember it well. That dazzling April moon…

Gingold: There was none that night. And the month was June. 

Most of us can recount similar conflicts with intimates and friends. Both parties to such disagreements typically remain thoroughly convinced that they are correct. On occasion the issues are settled when one person provides proof, but more often the disagreement ends in a standoff. 

Would more such disagreements be resolved if all of us could acquire the near perfect memory promised in popular books and courses? Not likely, based on the experience of the Russian journalist and mnemonist Shereshevski, described simply as S by the Russian neuropsychologist Alexander Luria. Throughout his life, S formed and retained vivid memories of just about everything that happened to him. Yet his prodigious memory proved more of a liability than an asset. Saddled with irrelevant and distracting details, S wore himself out and burdened others with long, enervating recollections that served no purpose. 

Memory was also a curse for relief pitcher Donnie Moore. The pitch that would live on in Moore’s memory occurred in the October 1986 American League playoffs between the California Angels and the Boston Red Sox. In the ninth inning of the fifth game, the Angels held a 5-4 lead. With a Red Sox runner on first base, and with two outs, Donnie Moore made the long trip from the bullpen to the pitcher’s mound to end the inning and clinch the playoffs for the Angels. Moore quickly threw two strikes against the hitter, Dave Henderson. After barely tipping the next pitch for a foul ball, Henderson connected on the next offering. He drove it into far left field for a home run that won the game and put Boston closer to its victory that season. Over the next three seasons, Moore’s memory of Henderson’s home run haunted him. “Tormented by the memory of one pitch,” as a bulletin from the Associated Press described him, afflicted with a deep depression, and beset by marital conflicts, Moore finally killed his wife before turning the gun on himself. Moore’s agent commented: “That home run killed him.” 

Donnie Moore and S, of course, are extreme examples of what can go wrong with memory. Most of us aren’t facing the extremes of too little or too much memory. Instead, we would gladly agree on a simple criterion: We want a memory that supports our goals and eases tasks of daily living, which means a memory superior to that of most people we encounter. 

We want a memory that supports our goals and eases tasks of daily living, which means a memory superior to that of most people we encounter. Unfortunately, even this modest goal is more difficult to achieve than it first appears.

Unfortunately, even this modest goal is more difficult to achieve than it first appears. Take 1999 National Memory champion Tatiana Cooley. Despite her ability to commit to memory vast amounts of information, Cooley relies in her daily life on to-do lists and sticky pads. What’s going on here? 


According to Daniel Schacter, chairman of the Harvard University psychology department, the puzzling disjunction between Cooley’s championship memory performance and “her forgetting-filled everyday life illustrates the difference between transience and absentmindedness.” 

Most of us experience episodes of absentmindedness daily. We remember to stop for our dry cleaning on our way home from work but forget that we are also out of milk and that the grocery store is next to the dry cleaners. On occasion the penalty for absentmindedness can be far harsher than a lack of milk in the fridge. In October 1999, musician Yo-Yo Ma’s absentmindedness almost cost him the loss of a $2.5 million cello. Exiting a cab he forgot that he had put the instrument in the trunk and walked off without it. Fortunately neither the cab driver nor the police shared Yo-Yo Ma’s absentmindedness, so he quickly recovered his prized cello. 

Why do these things happen, and how do they relate to Tatiana Cooley’s sticky notes? Our answer comes from the impressive insights into human memory achieved by neuroscientists over the last half-century. They have found that memory depends on the normal functioning of several midline brain structures, including the hippocampus—that sea-horsed shaped structure in the temporal lobe—along with its connections to other key structures such as the amygdala, the uncus, the hippocampal gyrus, and the medial thalamus. The importance of these structures in memory formation and retention emerged from careful observation of patients with brain damage in these areas. 

A patient known in the scientific literature only as HM lost the power to form new memories after the surgical removal of several of these structures on both sides of his brain. He became a famous exemplar of extreme “absentmindedness” and to this day cannot remember recently encountered people or events for more than a few moments. Since HM’s 1953 surgery, neuroscientists have studied other brain-injured patients who have similar difficulties with “declarative memory” (memory for material that can be consciously recalled and spoken about as contrasted, for example, to remembering how to skate). Like HM, these patients developed their memory problems after surgery or suffering injury or other damage to one or more critical midline brain structures.

It is likely that absentmindedness represents a “gentler” version of this dramatic forgetfulness, one that does not involve injury but rather an involuntary interference with our brain’s normal encoding. As Schacter puts it, absentmindedness involves information encoded improperly (or not at all) or information that is in our memory but cannot be called up at the moment we need to retrieve it. Multi-tasking and over-commitment contribute to absentmindedness in all of us because we are forced into mentally balancing more items than our brains can comfortably manage. As a result, we are preoccupied, our attention directed at something other than our immediate situation. A reliable memory requires that we overcome absentmindedness by paying attention to the things that we want to remember. Nothing startlingly new about that. All memory improvement programs suggest techniques for converting dry-as-dust material into vivid pictures or colorful situations that seize our attention. 

Multi-tasking and over commitment contribute to absentmindedness in all of us because we are forced into mentally balancing more items than our brains can comfortably manage.

I looked at some of the current programs for enhancing memory and found most helpful The Memory Pack by Andi Bell (Carlton Books 2000) and Memory Power by Jonathan Hancock (Barron’s 1997). Both authors won international memory contests; despite slight differences in their approach, both programs emphasize paying attention and trying to come up with ways of making the material to be memorized stand out from the general background. 


Absentmindedness is only one of the memory “sins” skillfully and entertainingly covered in Schacter’s new book The Seven Sins of Memory, to be published by Houghton-Mifflin in May 2001 and from which several of my examples are taken. The other six “sins” are transience, blocking, misattribution, suggestibility, bias, and persistence. 

“Transience, absentmindedness, and blocking are sins of omission,” writes Schachter. “We fail to bring to mind a desired fact, event or idea.” In contrast, misattribution, suggestibility, bias, and persistence are all sins of commission: We remember but our memories are incorrect or unwanted. 

No problem in understanding transience. Although you can recall what you had for dinner last night, your memory for dinner on the same day last week is much shakier (unless, of course, something out of the ordinary occurred, like a dropped drink or a heated argument). Transience, like absentmindedness, can be understood in terms of brain functioning. Simply put, over time specific memories shift from “high” to “low” definition as a result of neurons dropping out of the circuitry responsible for that specific memory. Conscious recollection is one way of preserving those circuits and thereby reversing this process. Indeed reminiscence is used therapeutically in many treatment facilities to preserve memory among older persons suffering from early dementia. 

In contrast with transience and absentmindedness, blocking is more a complicated and controversial concept. In common with the remaining memory “sins” covered in Schacter’s book, it is also less directly correlated with specific brain dysfunctions. Shopping with your spouse in a department store, you encounter a colleague from work. What should be a simple introduction turns into an agonizing search through your memory bank for the colleague’s name. Are you experiencing difficulty because you secretly dislike your colleague, as the Freudians would have it, or is something else going on? 

John Stuart Mill, rather than Freud, provides the common sense answer to that question. “Proper names are not connotative,” wrote Mill, “they denote individuals who are called by them: but they do not indicate or imply any attributes as belonging to those individuals.” Since every Mary in the world could just as well be named Jane or Sarah, there isn’t any totally reliable way of guaranteeing that you will be able to recall the name of that unexpectedly encountered colleague—unless, of course, you regularly employ one of the memory techniques suggested by Bell and Hancock to convert the name into an easily remembered image. 

For instance, if your colleague is named Mary Stewart, you might establish her identity in your mind as an image of a queen sitting on her throne. Or perhaps you envision an art student painting a still life of a bowl containing a stew with croutons in the form of women named Mary floating on it. Whatever image you choose should be dramatic and/or bizarre and therefore memorable. To be helpful, such mnemonic techniques must be regularly and consistently employed. 

Personally I find memory techniques based on vivid imagery helpful on the whole but nonetheless burdensome. After a while I find that the accumulated images start interfering with one another. Besides, not every person or event warrants the impressive expenditure of time and effort required to avoid coming up short when trying to retrieve the name of the occasional colleague encountered in a department store. 

I should add that practitioners of mnemonic techniques assure me that I am mistaken, that once adopted and frequently applied their techniques render memory failures a thing of the past. To settle the issue for yourself, I suggest that you try either The Memory Pack or Memory Power. Both are fun to work with and, speaking from my own experience based on a modest amount of time spent applying the methods, will provide you with helpful ways of rendering memory failures less persistent and bothersome. 


More bothersome than memory failure is “remembering” something that never happened, confusing the source of information that you do correctly recall or, most disturbing of all, repeatedly remembering disturbing events that you would prefer never to think of at all (the Donnie Moore effect). For instance, when did you first learn that George W. Bush was finally declared the winner in the recent Presidential election? Are you absolutely sure of the circumstances? Do not be too confident of the correctness of your recall; you may have inadvertently fallen victim to a form of misattribution that Schacter refers to as “source amnesia.” 

More bothersome than memory failure is “remembering” something that never happened, confusing the source of information that you do correctly recall or, most disturbing of all, repeatedly remembering disturbing events that you would prefer never to think of at all.

Source amnesia occurs, says Schacter, when “people recall correctly a fact they learned earlier, or recognize accurately a person or object they have seen before, but misattribute the source of their knowledge.” In the example of the election, your source amnesia results from the many separate discussions you held that day with various people about the final results. As a consequence, you may unwittingly have difficulty distinguishing one conversation from the other. Volunteers participating in psychological experiments on facial identification frequently misremember the time and place of a previous encounter with the person shown them in a picture or drawing. 

If you doubt that you could fall victim to the “sin” of misattribution, Schachter offers an exercise to test yourself. You listen to a list of words read to you by someone else (I recorded the words and then played the recording back). That list is followed by another. The object is to identify on the second list the words you heard on the first list. Sounds easy? Try the test yourself without looking ahead to Schacter’s revelation of the diabolical twist contained in this seemingly straightforward exercise. Unless you are a remarkably disciplined thinker, you will be guilty of one or more misattribution errors. 

Suggestibility also lends itself to testing. Unfortunately the testing procedures are too often conducted—with disastrous and tragic results—during the course of psychotherapy sessions and law enforcement interviews of people who have witnessed crimes. “Suggestive questioning by law enforcement officials has led to serious errors in eyewitness identification, and suggestive procedures used by psychotherapists have elicited memories of traumatic events [sexual abuse] that never occurred,” writes Schacter. Such errors can occur because of an innate tendency in all of us to “incorporate misleading information from external sources— other people, written materials or even the media—into personal recollections.” 

In a study assessing bias in college students, the student volunteers responded to questions about the personal qualities of their current romantic partners (for example, their honesty and intelligence). They also estimated their degree of affection for them. When asked to recall these evaluations two months later, the students’ recollections tended to correspond to their current rather than past evaluations and feelings. The same tendency occurred in married couples asked similar questions. “Those men and women whose feelings about one another had changed over time tended to mistakenly remember that they had always felt the same way,” Schacter tells us. “Trying to remember what they felt four years earlier...only one in five of those whose feelings had changed recalled accurately ‘the way they were.’ ” 

When we fall prey to the seventh and final memory “sin,” persistence, we tend, like Donnie Moore, to dwell on losses, embarrassing moments, or failed relationships. Not surprisingly, persistence thrives when we are depressed or emotionally overloaded. We ruminate about events and relationships that went badly and ignore those that turned out well, explains Schacter, because our emotions are closely linked with our perceptions, which in turn influence the formation of new memories. If this process of emotional misrepresentation continues long enough and with sufficient intensity, the ensuing gloom and despair can consume our entire life. 


Fortunately, all is not gloom and despair; we can take specific steps to overcome each of the seven “sins.” For example, misattribution is less likely if we pay careful attention to the source of our ideas. We should insist on dredging up from our memory not only a specific item of information but also the occasion when we learned it and who told it to us. Of course, this is not possible for many aspects of general knowledge (few of us can recall when and where we first learned that Abraham Lincoln was the 16th president). But for the details of our personal lives we should demand, according to Schacter, recollections of distinctive details of an experience before we are willing to say that we remember it. We can also counteract transience by relating the information we want to remember to information already comfortably in storage. This is the basis for the memory programs like those authored by Bell and Hancock. 

After learning about the seven sins and the general perils and impediments to accurate recollection, it is only too easy to conclude that human memory is deeply flawed. “To the contrary, I suggest that the seven sins are…a price we pay for processes and functions that serve us well in many respects,” writes Schacter. For instance, would you want to remember your telephone number from your college days or every grocery list you made this year? 

When Schacter seeks to explain the “sins” based on evolutionary psychology, he is not always entirely convincing, nor does he seem entirely convinced himself. He writes: “But how could one ever know about the relevant properties of environments during the hunter-gatherer period or even earlier periods that may be relevant to human evolution? Not easily.” 

Much more satisfying is his explanation that the sins of memory are best understood as by-products of useful features of memory that, while serving us well on the whole, occasionally get us into trouble. He says “absent-minded errors, misattribution...and suggestibility are, I suggest, by-products of adaptations...that produced a memory system that does not routinely reserve all the details required to specify the exact source of an experience.” Blocking, according to Schacter, may be “an incidental by-product of effects related to recency and frequency of information retrieval that also give rise to transience.” 


In addition to his psychological explanations, Schacter provides throughout entertaining and illuminating case histories of patients who suffered memory difficulties following brain injury. 

We learn of M.R., a photographer in his mid-forties who started believing that strangers he casually encountered were actually famous actors, television personalities, and other celebrities. So strong was the tendency for misattribution that eventually, in his own words, he was “seeing film stars everywhere.” At the urging of his wife, he sought neuropsychiatric help. Testing revealed abnormalities brought on by multiple sclerosis in his frontal lobes, specifically in an area important in facial recognition. When activated under normal circumstances this “facial recognition unit” sends out signals that provide a feeling of familiarity. But these signals do not provide any details concerning the identity of the person encountered. As a result of his frontal lobe damage, M.R. lost the ability to monitor signals generated by the “facial recognition unit.” As a result, total strangers appeared as familiar to him as the celebrities he saw on television and in the movies. 

Although Schacter is mostly even-handed in his selection of practical examples of memory research (such as post-traumatic stress and the perils of eyewitness identification), he occasionally opts for a political correctness that some readers might find off-putting. After establishing his take on the Monica Lewinsky matter (an “obsessive pursuit of Clinton by the independent counsel’s office”), Schacter suggests that Clinton’s “self-professed confusion about the details of what happened is exactly the type of forgetting expected based on both naturalistic and laboratory studies.” 

Before reaching this conclusion, Schacter should have considered an alternative explanation: With so much at stake in the Lewinsky matter, it seems reasonable Clinton and his handlers familiarized themselves with professional opinions on the subject of forgetting and memory lapses. Certainly any credible claim of memory failure as an explanation for Clinton’s inability to answer questions during his televised deposition had to be consistent with expert opinion on human memory and forgetting. 

These minor criticisms aside, The Seven Sins of Memory is a marvelous introduction to memory, the most fascinating and accessible aspect of contemporary neuroscience. 

Overall, The Seven Sins of Memory, The Memory Pack, and Memory Power illustrate just how far we have progressed since the pessimistic pronouncement about memory made by the character Fanny Price in Jane Austin’s Mansfield Park

The memory is sometimes so retentive, so serviceable, so obedient—at others, so bewildered and so weak—and at others again so tyrannic, so beyond control!—We are to be sure a miracle every way—but our powers of recollecting and forgetting do seem peculiarly past finding out. 

“Memory’s vices are also its virtues, elements of a bridge across time that allows us to link the mind with the world.”

Not only is Fanny wrong that memory is “peculiarly past finding out,” but, as Schacter reminds us, “the seven sins are not merely nuisances to avoid.” Rather, “memory’s vices are also its virtues, elements of a bridge across time that allows us to link the mind with the world.” 


From The Seven Sins of Memory by Daniel Schacter. ©2001 by Daniel Schacter. Reprinted with permission of Houghton Mifflin.

In George Orwell's chilling novel of life in a totalitarian political system, 1984, the ruling party achieved psychological mastery over its subjects by willfully altering the past. “Who controls the past,” ran the party slogan, “controls the future: who controls the present controls the past...” The government’s Ministry of Truth tried to alter the written historical record and even to manipulate the actual experience of remembering:

Past events, it is argued, have no objective existence, but survive only in written records and in human memories. The past is whatever the records and the memories agree upon...control of the past depends above all on the training of memory. To make sure that all written records agree with the orthodoxy of the moment is merely a mechanical act. But it is also necessary to remember that events happened in the desired manner. And if it is necessary to rearrange one’s memories or to tamper with written records, then it is necessary to forget that one has done so. The trick of doing this can be learned like any other mental technique. 

Totalitarian societies like the one envisioned by Orwell have declined since the collapse of the eastern European communist regimes. But forces that in some sense resemble the Ministry of Truth continue to operate in individual minds: our memories of the past are often re-scripted to fit with our present views and needs. The sin of bias refers to distorting influences of our present knowledge, beliefs, and feelings on new experiences or our later memories of them. In the stifling psychological climate of 1984, the Ministry of Truth used memory as a pawn in the service of party rule. Much in the same manner, biases in remembering past experiences reveal how memory can serve as a pawn for the ruling masters of our cognitive systems. 

Five major types of biases illustrate the ways in which memory serves its masters. Consistency and change biases show how our theories about ourselves can lead us to reconstruct the past as overly similar to, or different from, the present. Hindsight biases reveal that recollections of past events are filtered by current knowledge. Egocentric biases illustrate the powerful role of the self in orchestrating perceptions and memories of reality. And stereotypical biases demonstrate how generic memories shape interpretation of the world, even when we are unaware of their existence or influence. 

THE WAY WE WERE DEPENDS ON THE WAY WE ARE When Ross Perot unexpectedly announced his withdrawal from the presidential race on July 16, 1992, he dealt a cruel blow to his fervent supporters. Perot was widely reviled in the press—Newsweek ran a cover story on him titled “The Quitter”—and his allies experienced a complex mixture of sadness, anger, and hope that he might reconsider the decision. When he re-entered the campaign in early October, those who had supported him reacted in different ways. Loyalists never wavered from Perot and renewed their efforts on his behalf. Returning supporters had initially switched to another candidate but quickly came back. Deserters abandoned Perot as soon as he left the race and never returned.

A few days after Perot quit in July, the University of California at Irvine psychologist Linda Levine asked his supporters how they felt; she then probed their memories again after the election in November. Loyalists, returning supporters, and deserters all accurately recalled, at least to some degree, the sadness, anger, and hope they had felt when Perot made his stunning July announcement. But they also rewrote their memories to be consistent with how they felt in November. After the election, loyalists underestimated how sad they felt when Perot quit. Returning supporters recalled feeling less angry in July than they actually said they were at the time. And deserters recalled being less hopeful than they actually were. 

This consistency bias has turned up in several different contexts. Recalling past experiences of pain, for instance, is powerfully influenced by current pain level. When patients afflicted by chronic pain are experiencing high levels of pain in the present, they are biased to recall similarly high levels of pain in the past; when present pain isn’t so bad, past pain experiences seem more benign, too. Attitudes toward political and social issues also reflect consistency bias. People whose views on political issues have changed over time often recall incorrectly past attitudes as highly similar to present ones. In fact, memories of past political views are sometimes more closely related to present views than to what people actually believed in the past. In one study, high school students stated their opinions on school busing, and then heard arguments for or against busing. Despite changing their views in line with the arguments they heard, the students mistakenly recalled that they had always held the views they expressed after hearing the pro or con argument. 

To appreciate why people are so prone to consistency biases, try to recall your views on capital punishment five years ago. Can you specifically recall what you believed in those days? The Canadian social psychologist Michael Ross has observed that people often do not have clear memories of exactly what they believed or felt in the past, and instead infer past beliefs, attitudes, and feelings from their current states. Unless there is good reason to believe that your views on capital punishment have changed, you are likely to assess your present opinion and assume you felt the same way five years ago. Invoking what Ross calls an “implicit theory of stability” will lead to accurate recall if your views haven’t changed over time, but will produce a consistency bias if they have. 

People don’t always invoke a theory of stability, however; sometimes we believe that we have, or should have, changed over time. Self-help programs may exploit such feelings. Once people invest time and energy in a program that is supposed to help them change— lose weight, prepare for college entrance exams, or exercise more—they may exaggerate the degree of change they’ve actually experienced. Students who completed a program purported to enhance their study skills remembered their initial level of skill as being lower than they said before beginning the program, whereas students who were on a waiting list for the program showed no change bias. 

Change bias also influences how women recall their emotional states during menstruation. Surveys indicate that women generally believe that they are likely to become highly irritable and depressed during periods. Studies of women during menstruation clearly show heightened incidence of such physical symptoms as backaches, headaches, and abdominal pains—but there’s little evidence for greater depression or related mood changes. Physical discomfort may lead women to theorize the menstruation results in negative moods and related kinds of psychological distress. In a study from Michael Ross’ group, women who were menstruating reported more physical symptoms compared to when they were not, and showed little change in self-reported mood or personality measures. Yet during menstruation, these women recalled inter-menstrual emotional states as more positive than they actually were, supporting their theories that menstruation produces bad moods. Such theories can also inflate recall of negative menstrual symptoms: the more a woman believes that she experiences bad moods during menstruation, the more she shows exaggerated recall of such symptoms after her period has concluded.

About Cerebrum

Bill Glovin, editor
Carolyn Asbury, Ph.D., consultant

Scientific Advisory Board
Joseph T. Coyle, M.D., Harvard Medical School
Kay Redfield Jamison, Ph.D., The Johns Hopkins University School of Medicine
Pierre J. Magistretti, M.D., Ph.D., University of Lausanne Medical School and Hospital
Robert Malenka, M.D., Ph.D., Stanford University School of Medicine
Bruce S. McEwen, Ph.D., The Rockefeller University
Donald Price, M.D., The Johns Hopkins University School of Medicine

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