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Posts tagged ‘Memory’

The Importance of Forgetting: Why a Bad Memory is a Good Memory

I wish my memory was like a computer’s. I’ve lost car keys, a cellphone, a driver’s license and on the eve of an overseas trip, a passport; wouldn’t things be easier if I could effortlessly organize millions of pieces of information and retrieve them like with a mental Google search?

Alas, my memory – and yours – evolved according to different plans. Instead of neatly storing pieces of information into a neural bookshelf, memory organizes itself more like a web where experiences are stored contextually and in relation to one another. “An item is stored in relation to other items,” neuroscientist Dean Buonomano explains, “and its meaning is derived from the items to which it is associated.” This is why, for instance, thinking about “Africa,” “Animal,” “Stripes,” and “Black and White” automatically pops “Zebra” into your conscious mind. And as Proust famously illustrated in his lengthy classic Remembrance of Things Past, a single recognized combination of taste and smell can trigger an avalanche of memories.

At its extreme, our imperfect memory is sometimes the difference between life and death. About 6 percent of skydiving deaths are caused by forgetting to tug on the rip-chord and scuba divers too often forget to check their oxygen cage. It is also responsible for numerous false eye-witness accounts, including that of rape victim Jennifer Thompson, which landed the innocent Ronald Cotton in jail for 11 years. In addition, our tendency to foolishly believe that so-called “flashbulb” memories are accurate isn’t very impressive.

Indeed, our memory is far from perfect. However, is this a bad thing? A recent Scientific American Mind article by Ingrid Wickelgren suggests that for all its setbacks memory is a fairly well oiled cognitive capacity. She explains:

For most people, the concept of forgetting conjures up lost car keys, missed appointments and poor scores on exams. Worse, it augurs dementia. Psychologists traditionally shared this view, and most of them studied memory with an eye toward closing the cracks through which knowledge can slip… An early challenge to that downbeat view of forgetting emerged in 1970, when psychologist Robert A. Bjork, now at the University of California at Los Angeles, reported that instructions to forget some learned items could enhance memory for others. Forgetting is therefore not a sign of an inferior intellect—but quite the opposite. The purpose of forgetting, he wrote, is to prevent thoughts no longer needed from interfering with the handling of current information—akin to ridding your home of extraneous objects so that you can find what you need.

Memory is much more efficient in this light. Because 99 percent of our experiences are fairly uneventful and meaningless, the mind does a good job of only holding onto the important stuff while discarding the rest. Sure there are obvious downsides to this, but there are upsides also. Wickelgren goes onto explain the importance of forgetting:

In a study published in 2001 [Michael C.] Anderson and his student Collin Green… gave 32 college students what they called a think/no-think task. The students learned 40 word pairs such as ordeal-roach, with the first word serving as a cue for the second. Next they presented the cues and asked participants either to think about and say the word that went with it or to suppress (not think about) the associated word. Suppression seemed to work. The students even recalled fewer of the suppressed word associations than the “baseline” words—ones they learned but neither practiced nor inhibited…

[But] forgetting does not come easily to everyone…. This skill, or lack of it, has ripple effects on personality. If you cannot shake negative memories, for example, you might be easily sucked into a bad mood. Although the inability to forget does not cause depression, research shows that depressed patients have difficulty putting aside dark thoughts. In one experiment, published in 2003, psychologist Paula T. Hertel of Trinity University in San Antonio and Melissa Gerstle, now at the Texas Children’s Hospital and Baylor College of Medicine, found that depressed students recalled many more words they had practiced suppressing than other students did. The students who had the most trouble forgetting scored the highest on measures of rumination—which is the tendency to dwell on a concern—and the frequency of unwanted thoughts.

Those who do not suffer from depression, on the other hand, benefit from the brain’s natural tendency to remember the good and forget the bad. This cognitive advantage influences us to remember a spoiled camping trip as a “great time” with friends or a disastrous trip to Disney World as a “good bonding experience” for the family. It also seems to cause women to only remember the good parts of childbirth – the end; a nice evolutionary quark that influences them to continue reproducing. Perhaps most importantly, the brain’s automatic ability to forget the bad helps people get over most personal losses, emotional trauma and bad breakups. As Jim Carrey’s character Joel Barish illustrates in the movie Eternal Sunshine of the Spotless Mind, people will go a long way to forget certain experiences if they cannot do so naturally. With this in mind, I’m glad my memory is not like a computer.

If there is a bottom line it is this. The purpose of human memory is not to store information but to organize information so we can understand and predict the world. The downsides of this abound, but I say evolution did a pretty good job. Car keys, cell phones, licenses and passports weren’t very important over the last few million years when our ancestors were evolving, after all.

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The Past & Future: Where Are Brains Supposed to Exist?

Funny stuff happens when people think about the past. Sometimes, they replace reality with fiction. This is because we have poor episodic memories – a well-established fact in psychology. Consider the famous study done by Ulric Neisser. The day after the Challenger disaster he asked Emory University undergrads to write a description of how they heard of the disaster – the time of day, what they were doing, how they felt about it, etc. Neisser then asked the same students the same set of questions two and a half years later and compared the two descriptions. He found three things. First, the memories of the students had dramatically changed: “twenty-five percent of the students’ subsequent accounts were strikingly different from their original journal entries. More than half the people had lesser degrees of error, and less than ten percent had all the details correct.” Second, people were usually confident that the accounts they provided two and a half years later were accurate. And third, “when confronted with their original reports, rather than suddenly realizing that they had misremembered, they often persisted in believing their current memory.”

The study, which is now known as the Challenger study, has been replicated with several notable events such as 9/11 and the Reagan assassination attempt (Neisser also ran a similar experiment in the 1970s that compared John Dean’s testimony before the Watergate Investigation Committee with the actual tape recordings. Although the press labeled Dean as the “human tape recorder” Neisser found that his memory was not nearly that accurate).

In another report, psychologist Daniel Offer interviewed 73 people a series of social questions and compared the answers they gave in 1962 with ones in the 1990s. He found that “nearly half believed they had said it was acceptable to start having sex during high school, though only 15 percent had given that answer. Only one in three now recalled receiving physical punishment, though as ninth-graders 82 percent said they had.”

So why are our memories so bad? For one thing, memories do not work like computers. As much as it feels like we retrieve memories in the same way that we retrieve word documents, the reality is much different. When we remember, we are actually thinking about the last the time we thought about a memory. In other words, our memories are really just memories of memories of memories etc. Here is the key: whenever we remember an event, we usually add or remove something. For example, if I think about my first memory – a squirrel getting stuck in my room when I was three – I picture my grandfather and brother there, and it being nighttime. But I know from my family members that none of these things are true.

All of this suggests that brains are not built for the past. Unfortunately, psychology also tells us that they are not built for the future either. Don’t think so? Meet Philip Tetlock, a psychologist from the University of Pennsylvania who spent 18 years gathering data to measure how good the “experts” are at predicting future events. This included academics, journalists, intelligence analysis, and think-tank members who appeared on television, got quoted in the paper, and advised governments and businesses. He asked them to rate the probability of something – an economic, political, or military event – increasing, decreasing, or remaining the same, and measured their results (For example, one question was the “central-government debt will either hold between 35% and 40% of GDP or fall below or rise about that range”). Turns out, they were no better than chance. As one New Yorker article puts it, “human beings who spend their lives studying the state of the world… are poorer forecasters than dart-throwing monkeys, who would have distributed their picks evenly over the three choices.” Why? Put simply, we are horrible at predicting specific future events.

ESPN baseball writer Jayson Stark is one of the few experts to admit this. He begins his 2011 MLB preview column by saying that “after 11 years of writing this same, ill-fated column, I’ve finally figured out two things: (A) It’s hopeless. And (B) it’s for entertainment purposes only.” He is right. Sports Illustrated, ESPN, and other sports outlets consistently get their predictions very wrong. This shouldn’t be a surprise. Seasons are filled with unpredictable injuries, random events, and bad officiating that can make or break championship runs. The same can be said of political campaigns, business ventures, and the economy – systems that are far more complex than a Major League Baseball season. In a globalized world where there are infinite inputs, long-term detailed predictions are simply impossible.

You don’t need all of this psychological data to know that humans are bad when it comes to dealing with the past and future. Budda knew this long before Wilhelm Wundt and Sigmund Freud when he said “do not dwell in the past, do not dream of the future, concentrate the mind on the present moment.” The difficult part is, of course, actually doing this. Living in the moment might be the ultimate “easier said than done,” especially if you just experienced a break-up, divorced, or got fired.

To be sure, psychology isn’t saying that we should throw the baby out with the bathwater. Generally speaking, our knowledge of the past and future is pretty good; we know where we grew up, who are parents are, how to do basic math, what the 50 states are, and we also know that winter will come in six months and exercise and eating healthy will be good for us in the long run. But in terms of specifics? Forget it.

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