Remember the warehouse at the end of Raiders of the Lost Ark? That cavernous facility housed crate after crate of top-secret government treasures. Like that warehouse, our brains have a seemingly endless capacity for storage. When scientists try to quantify how much information the brain can learn, the numbers are so high that they’re practically infinite. So why is it sometimes so hard to remember what we know? Our problem is not storage—it’s accessibility.
Many of us have experienced the “tip of the tongue” syndrome. You know you know something, like the name of an actor, the answer to a trivia question, or an important fact on your board exam, but you just can’t seem to access it quickly in the moment you need it. Why is that? According to learning researcher Robert Bjork, there is a crucial distinction between storage, which is unlimited, and retrieval, which is limited.
Once you learn and understand a piece of information (and understanding is key), it is moved from short-term to long-term memory—the warehouse. But this is only the first step in remembering. To be able to access that stored knowledge, we must reinforce it by retrieving it. And according to Bjork, one of the most unintuitive things about this process is that for any given memory, the “higher the current retrieval strength”—the easier it is to remember right now— “the smaller the gains in storage strength that result from additional study or practice.”
Let’s break that down: If it’s easy for you to remember something right now, you won’t gain much from studying it right away. You must wait until it is hard to remember before you’ll get anything out of studying. That sure goes against our inclinations! But learning theorists believe that memory is only improved when we forget something and then retrieve it, for “as you forget, you create the potential to reach a new, higher level of learning.”
There is another aspect to this process: associations. If information is not stored near similar information, it becomes harder to find. That is why all new knowledge must be connected to old knowledge before our brains can catalog it.