The problem of forgetting might not torment us so much if we could only convince ourselves that remembering isn't important. Perhaps the things we learn — words, dates, formulas, historical and biographical details — don't really matter. Facts can be looked up. That's what the Internet is for. When it comes to learning, what really matters is how things fit together. We master the stories, the schemas, the frameworks, the paradigms; we rehearse the lingo; we swim in the episteme.
The disadvantage of this comforting notion is that it's false. "The people who criticize memorization — how happy would they be to spell out every letter of every word they read?" asks Robert Bjork, chair of UCLA's psychology department and one of the most eminent memory researchers. After all, Bjork notes, children learn to read whole words through intense practice, and every time we enter a new field we become children again. "You can't escape memorization," he says. "There is an initial process of learning the names of things. That's a stage we all go through. It's all the more important to go through it rapidly." The human brain is a marvel of associative processing, but in order to make associations, data must be loaded into memory.
Once we drop the excuse that memorization is pointless, we're left with an interesting mystery. Much of the information does remain in our memory, though we cannot recall it. "To this day," Bjork says, "most people think about forgetting as decay, that memories are like footprints in the sand that gradually fade away. But that has been disproved by a lot of research. The memory appears to be gone because you can't recall it, but we can prove that it's still there. For instance, you can still recognize a 'forgotten' item in a group. Yes, without continued use, things become inaccessible. But they are not gone."
After an ichthyologist named David Starr Jordan became the first president of Stanford University in the 1890s, he bequeathed to memory researchers one of their favorite truisms: Every time he learned the name of a student, Jordan is said to have complained, he forgot the name of a fish. But the fish to which Jordan had devoted his research life were still there, somewhere beneath the surface of consciousness. The difficulty was in catching them.
During the years that Wozniak struggled to master English, Bjork and his collaborator, Elizabeth Bjork (she is also a professor of psychology; the two have been married since 1969), were at work on a new theory of forgetting. Both were steeped in the history of laboratory research on memory, and one of their goals was to get to the bottom of the spacing effect. They were also curious about the paradoxical tendency of older memories to become stronger with the passage of time, while more recent memories faded. Their explanation involved an elegant model with deeply counterintuitive implications.
Long-term memory, the Bjorks said, can be characterized by two components, which they named retrieval strength and storage strength. Retrieval strength measures how likely you are to recall something right now, how close it is to the surface of your mind. Storage strength measures how deeply the memory is rooted. Some memories may have high storage strength but low retrieval strength. Take an old address or phone number. Try to think of it; you may feel that it's gone. But a single reminder could be enough to restore it for months or years. Conversely, some memories have high retrieval strength but low storage strength. Perhaps you've recently been told the names of the children of a new acquaintance. At this moment they may be easily accessible, but they are likely to be utterly forgotten in a few days, and a single repetition a month from now won't do much to strengthen them at all.
The Bjorks were not the first psychologists to make this distinction, but they and a series of collaborators used a broad range of experimental data to show how these laws of memory wreak havoc on students and teachers. One of the problems is that the amount of storage strength you gain from practice is inversely correlated with the current retrieval strength. In other words, the harder you have to work to get the right answer, the more the answer is sealed in memory. Precisely those things that seem to signal we're learning well — easy performance on drills, fluency during a lesson, even the subjective feeling that we know something — are misleading when it comes to predicting whether we will remember it in the future. "The most motivated and innovative teachers, to the extent they take current performance as their guide, are going to do the wrong things," Robert Bjork says. "It's almost sinister."
