We sometimes think of our memories as a sort of mental DVD or computer disk where our brains record things that happen to us. You have pancakes for breakfast, your mind makes a recording of the event, then later in the day when someone asks you what you had for breakfast, your mind sort of sticks in the DVD or consults the file (kind of like Data from Star Trek except your eyes don’t zig back and forth really fast) then whammo, you have it. “Pancakes,” you say with confidence.
Same thing with information. Your teacher asks you the capital of Nebraska, your brain (very, very quickly) consults the memory file marked “States, capitals of” and you proudly announce “Lincoln,” unless your state-capitals file was made when you weren’t paying much attention, in which case you might say “Denver,” or just “What?”
It’s a nice little image, but as far as scientists can tell memory really doesn’t work quite that way. For one thing, there are several types of memory, not just one: long-term memory, short-term memory, working-memory, sensory-memory. You get the idea. And each kind of memory works a little differently from the others.
And memory is not anywhere near as reliable as computer files or DVDs. We don’t always remember things accurately, some memories fade over time, and it is pretty easy to introduce false memories. Scientists studying the reliability of eye-witness testimonies have found that if they show a group of people a videotape of a car crash and then ask them questions about it, the answers they get depend on the questions they ask. For example, in one experiment they asked people who had watched the tape, “Did the blue car run the stop sign?” Some said “definitely yes.” Others said “definitely no.” Not very many pointed out that there wasn’t a blue car in the videotape they watched. There wasn’t. They weren’t lying. It was just that once the researchers had mentioned a blue car, people “remembered” seeing it.
The mood you were in and your surroundings when you learned something also makes a difference in how well you recall it later. If you are calm and relaxed when studying for a test, but anxious when you take the test, you may have more trouble remembering the material you learned while you were calm.
And try this trick. The next time you start to say something and forget what you were about to say, go back to exactly what you were doing when you started to say it and “pick up the thought.” Let’s say that while you are eating lunch at school you want to tell your friend about something funny that happened last night. But when you get back to class and see the friend you can’t remember what it was you were going to tell him. Go back to the lunchroom to the table where you were sitting, and chances are you’ll remember what you meant to say. Of course, then you have to remember it all over again until you get back to class. If you aren’t careful you could spend the day walking back and forth between the lunchroom and the classroom.
As important as it is to be able to remember things, it is just as important to be able to forget. Your brain can manage only so much information. From time to time you need to dump some data to make room for more. So if a couple of years from now you can no longer remember all those state capitals, don’t worry. You’ll be making room for other information – oh, say, your driver’s license number.