Why the brain forgets: it's perfectly normal for your memory to occasionally let you down. Here's why - Nurture The Whole You

NO DOUBT YOU KNOW HOW frustrating it can be to suffer a memory lapse. How many passwords do you have to remember just to access your voice mail at the office or your cell phone, not to mention the Internet? Have you ever had to apply for a temporary PIN at a website because you've forgotten your permanent number? I certainly have.

It's tempting to think that Mother Nature committed a blunder in burdening us with such a faulty memory system. But on the contrary, memory problems are the byproducts of otherwise adaptive features of memory--a price we pay for processes that serve us well.

Indeed, during my 20 years of studying memory I've found that there are explanations for why we forget things. Here's what's going on in your brain when that happens.

Why Your Memories Fade

Passage of time is memory's most obvious enemy. You can probably easily recall what you've been doing for the past several hours. But if I ask you about those activities six weeks, six months, or six years from now, chances are you'll remember very few details. This type of memory lapse, called transience, can occur rapidly--over the course of a few seconds, like when you dial directory assistance for a phone number and then promptly forget it--or over the course of weeks, months, or years.

Sometimes you literally lose this information. The complex chemical changes that connect neurons and help encode memories when you experience an event or acquire new facts weaken over time. Unless you retrieve the information regularly, the connections weaken to the point where recall is impossible.

Yet other times, vague impressions of familiarity or fragmentary details of experiences are signs that the information is still somewhere in your memory. Countless studies have shown that you can recover lost information with cues that remind you of how you initially encoded it.

In addition to the passage of time, your daily life can exacerbate transience. For example, you're more likely to remember what you did at work on Monday if you go on vacation for the rest of the week than if you work every day till Friday. Carrying out similar duties each day at work makes the tasks generic, which interferes with your ability to recall.

Why You Can't Find Your Glasses

Even people with stellar memories lose things. You lose glasses and keys either because your brain never encoded an event or piece of information or because a cue devised to trigger your memory failed. For example, you may not have registered the action of putting your glasses on the edge of the couch while you were reading.

When you can't find them it's because your brain never encoded that memory. Or if you were aware that you'd placed your glasses in the drawer of the table on which you kept the book you're reading, and then that book (your visual cue to remind you that your glasses are in the table drawer) was moved, you may forget where your glasses are. In this case, your brain formed the memory; the cue you set up for yourself simply failed.

Absent-mindedness over tasks like forgetting to pick up a gallon of milk at the store also occurs because of missed cues. There are two types of memory cues for remembering tasks: event-based, like those triggered by the arrival of a friend (I'll leave for my appointment when Bill shows up) or time-based, those triggered by a particular time (I'll leave for my appointment at noon). If your friend doesn't show up or you forget to check your watch, you may forget your appointment.

Don't worry that each new memory slip signals the onset of age-related cognitive decline, or perhaps even Alzheimer's disease. While aging does hinder time-based memory (probably because it requires you to remember to set up the memory cues yourself), several studies have shown that older adults in their 60s and 70s perform almost as well as younger adults in event-based memory tests.

Why You Can't Recall Names

Blocking refers to those times when you have a word or name on the tip of your tongue, but you just can't recall it. Your brain has stored the elusive name or word and the object or person may be right in front of you, yet you still can't think of that word. Blocking on the names of familiar people is particularly embarrassing and frustrating. It's the single most common memory complaint of adults older than 50.

People's names are difficult to remember because they don't give you any information about an individual. If I tell you my friend's name is John Baker, I tell you little about him because the proper name "Baker" stands on its own. If I tell you that my friend is a baker, however, I tell you quite a bit about him. You probably know at least several characteristics of bakers: They work in a kitchen, bake bread, and get up early. In your mind these concepts all converge directly on the word "baker," helping you to recall the word.

A proper name may also conjure up several conceptual facts about a person--"attorney," "good golfer"--but these concepts converge on the identity of the person, not the name itself. Your brain then has to go one step further to the words "John" and "Baker" in order to recall the person's name. The name, therefore, remains just out of reach.

Why You Need to Forget

Imagine if your memory did not undergo transience or blocking. If someone asked you to recall an episode from your life that involved a table, you could probably think of a specific incident. Now imagine that the table cue brought forth the hundreds or thousands of table memories you have stored away in your brain. It would be like doing an Internet search and sorting through thousands of search engine results. It would be chaos.

Absent-mindedness is also important. It allows you to focus on matters that need attention, rather than on unimportant details. If you noticed all things with the same degree of attention, your mind would be cluttered with piles of useless information. These three flaws, in fact, demonstrate why memory works as well as it does.

CONSIDER THIS

Strengthen Your Memory

YOU CAN'T AVOID MEMORY LAPSES ENTIRELY, BUT YOU CAN TAKE steps so they occur less often.

WHEN YOU MUST REMEMBER SOMETHING

* CREATE GOOD CUES. Make your reminder cues both informative and obvious. The classic memory aid of tying a string around your finger meets the second criterion (you can see it) but may not meet the first (if you can't remember what the string is supposed to represent).

* CONVERT YOUR CUES. Time-based cues (call Lisa at 6 p.m.) are more difficult to remember than event-based ones (call Lisa when dinner is delivered). So stop relying on the clock and link what you need to remember with an activity that's sure to happen.

WHEN A NAME'S ON THE TIP OF YOUR TONGUE

* KEEP TRYING. Forgotten names often come to you within a minute. But even if they don't, don't give up: Studies show the more time you spend trying to retrieve a blocked name, the more likely you are to remember it.

* AVOID MISTAKES. While struggling to recall a forgotten name, don't endlessly repeat incorrect ones. It's tempting to do this, but the repetition of the wrong word will interfere with your ability to retrieve the word you're searching for.

* RUN THROUGH YOUR ABCs, Studies show that a name's initial letters are a more effective memory aid than information about the person. Therefore, you may find it helpful to go through each letter of the alphabet to see if one of them brings the name to mind.

Daniel L. Schacter, Ph.D., is chairman of the psychology department at Harvard University in Cambridge, Mass.

COPYRIGHT 2001 Weider Publications
COPYRIGHT 2001 Gale Group