only built into the biology of memory. It is the very basis of memory—and identity. New memory traces are laid down on top of a foundation of old memories, and old memories can only be recalled in a context of recent experiences. Imagine a single painting being created over the course of a lifetime on one giant canvas. Every brush stroke coming into contact with many others can be seen only in the context of those prior strokes—and also instantly alters those older strokes. Because of this, no recorded experience can ever be fully distinct from anything else. Whether one likes it or not, the past is always informed by the present, and vice versa.
Scores of experiments confirm the malleability of old memories, and horror stories of False Memory Syndrome are by now widespread. The psychologist Elizabeth Loftus has spent the better part of her career documenting the ease with which false memories can be planted—accidentally or on purpose. Often, these false memories lead to wrongful convictions. In 1979, twenty-two-year-old marine corporal Kevin Green was convicted of second-degree murder for the brutal beating of his wife and the death of their full-term fetus. His wife had testified after coming out of a coma that Green, her own husband, was the attacker. Sixteen years later, the real attacker, a total stranger, confessed to police about that and six other murders. It turned out that Green’s guilt had been suggested to his wife early on in her rehabilitation. By the time it came to trial, she had created a memory so clear that she was able to confidently testify against her husband.
“Eyewitness misidentification … is known as the single greatest cause of the conviction of the innocent,” says attorney Barry Scheck. He describes a typical scenario: “You can have as many as five witnesses who begin in kind of a soft way, saying, ‘That might be the guy,’ and then, like wet concrete hardening, the [memories] get fixed to the point that by the time they get to the courtroom, they’re saying ‘That’s the man.’”
Part of the deep attraction to the idea of distinct memory molecules was that it connoted the ability to replay old memories like videotapes on a VCR—just as they were originally recorded. But the biology of memory constellations dictates that there is no such thing as pure memory. Recall is never replay.
But why? Why would millions of years of evolution produce a machine so otherwise sophisticated but with an apparent built-in fuzziness, a tendency to regularly forget, repress, and distort information and experience?
The answer, it turns out, is that fuzziness is not a severe limitation but a highly advanced feature. As a matter of engineering, the brain does not have any physical limitations in the amount of information it can hold. It is designed specifically to forget most of the details it comes across, so that it may allow us to form general impressions, and from there useful judgments. Forgetting is not a failure at all, but an active metabolic process, a flushing out of data in the pursuit of knowledge and meaning.
We know this not just from brain chemistry and inference, but also because psychologists have stumbled upon a few individuals over the years who actually could not forget enough—and were debilitated by it.
In his New Yorker profile, Mark Singer wonders if Martin Scorsese is such a person—burdened by too good a memory.
Was it, I wondered, painful to remember so much? Scorsese’s powers of recall weren’t limited to summoning plot turns or notable scenes or acting performances; his gray matter bulged with camera angles, lighting strategies, scores, sound effects, ambient noises, editing rhythms, production credits, data about lenses and film stocks and exposure speeds and aspect ratios.… What about all the sludge? An inability to forget the forgettable—wasn’t that a burden, or was it just part of the price one paid to make great art?
For some perspective on the inability to forget, consider the case study that psychologists call S. In the 1920s, S. was a twenty-something newspaper reporter in Moscow who one day got into trouble with his editor for not taking notes at a staff meeting. In the midst of the reprimand, S. shocked his boss by matter-of-factly repeating everything that had been said in the meeting—word for word.
This was apparently no stretch at all for S., who, it emerged upon closer examination, remembered virtually every detail of sight and sound that he had come into contact with in his entire life. What’s more, he took this perfect memory entirely for granted. To him, it seemed perfectly normal that he forgot nothing.
The editor, amazed, sent S. to the distinguished Russian psychologist A. R. Luria for testing. Luria did test him that day, and for many other days over a period of many decades. In all the testing, he could not find any real limit to his capacity to recall details. For example, not only could he perfectly recall tables like this one full of random data after looking at them for just a few minutes:
And not only could he efficiently recite these tables backwards, upside down, diagonally, etc., but after years of memorizing thousands of such tables he could easily reproduce any particular one of them, without warning, whether it was an hour after he had first seen it, or twenty years. The man, it seemed, quite literally remembered everything.
And yet he understood almost nothing. S. was plagued by an inability to make meaning out of what he saw. Unless one pointed the obvious pattern out to him, for example, the following table appeared just as bereft of order and meaning as any other:
“If I had been given the letters of the alphabet arranged in a similar order,” he remarked after being questioned about the 1–2–3–4 table, “I wouldn’t have noticed their arrangement.” He was also unable to make sense out of poetry or prose, to understand much about the law, or even to remember people’s faces. “They’re so changeable,” he complained to Luria. “A person’s expression depends on his mood and on the circumstances under which you happen to meet him. People’s faces are constantly changing; it’s the different shades of expression that confuse me and make it so hard to remember faces.”
Luria also noted that S. came across as generally disorganized, dull-witted, and without much of a sense of purpose or direction in life. This astounding man, then, was not so much gifted with the ability to remember everything as he was cursed with the inability to forget detail and form more general impressions. He recorded only information, and was bereft of the essential ability to draw meaning out of events. “Many of us are anxious to find ways to improve our memories,” wrote Luria in a lengthy report on his unusual subject. “In S.’s case, however, precisely the reverse was true. The big question for him, and the most troublesome, was how he could learn to forget.”
What makes details hazy also enables us to prioritize information, recognize and retain patterns. The brain eliminates trees in order to make sense of, and remember, the forests. Forgetting is a hidden virtue. Forgetting is what makes us so smart.
One of the worst things that I have to do is put on my pants in the morning. This morning I kept thinking there is something wrong because my pants just didn’t feel right. I had put them on wrong. I sometimes will have to put them on and take them off half a dozen times or more.… Setting the washing machine is getting to be a problem, too. Sometimes I’ll spend an hour trying to figure out how to set it.
—B.
San Diego, California
Taos
“Ten years to a cure,” a Japanese scientist whispered to me in our hotel lobby as we waited for the shuttle bus to the Taos Civic Plaza.
The whisper was as telling as the words. He couldn’t contain his optimism, and yet he also couldn’t afford to put it on display.
Other Alzheimer’s researchers had lately been adopting a similar posture. As scientists, they were reserved by nature. But the recent acceleration of discovery had made them a little