Why is it that, in an ordinary human brain, some memories last just a few minutes and then vanish, while others persist for days or months, even a lifetime? A big part of the answer lies in the way the memory is encoded, or converted into the kind of data the brain understands. The more elaborately we encode information at the time of learning, the sturdier and more robust the resulting memory will be, especially if we personalize it.
Many of us struggle to remember names. If, at a social event, you need help remembering the name Theresa, it helps to repeat the name internally, with additional information added. “Theresa is wearing a green dress. My second favorite color is green.” At first glance, this notion seems counterintuitive. Making information more elaborate means it becomes more complicated, which sounds like it would be more taxing for the memory system. But study after study shows that the complexity equates to greater learning. If the impact of the initial stimulus is deep and elaborate, the quality of the memories will be high, and their lifespan long.
This notion of elaborate and rich encoding is critical for making new information stick in the short-term memory. But how do you go beyond that, and intentionally congeal memories into long-term storage? In his book Brain Rules, scientist John Medina says the key to this is repetition at precisely timed intervals: “Memory may not be fixed at the moment of learning, but repetition, doled out in specifically timed intervals, is the fixative.”
The lion’s share of memories disappear within minutes, but reexposing oneself to information a few minutes, or even an hour or two after the initial encounter with it, will help to keep the information in the working memory. The more repetition cycles we give to a certain memory experience, the more likely it is to persist in our accessible mind.
A large body of research also shows that thinking about or discussing an event immediately after it occurs greatly enhances retrieval ability. This practice can also convert short-term memories into a long-term, more permanent form.
If we really dig into studying a new activity or subject—and strive to synthesize the new information into a big-picture context that we have previously learned—then the physical brain actually changes, and the memories can become vivid and durable. But memories are so capricious and volatile that, from there, we have to repeat to remember. If we repeat and revisit them often, discuss them with others, and meditate on their significance, then we can make them a part of us that we can carry on for many years.