Short Term vs Long Term Memory

Anytime we have an experience or learn something, our brain stores it as new information. Sometimes it is stored for years, sometimes only moments. There are still unanswered questions about what exactly determines whether information gets transferred to long-term memory or not. But there are a few basic properties of short and long term memory that scientists understand.

What is short term memory?

Our brains are constantly receiving sensory input. Whether through sight, sound, or touch, our brains have to quickly decide whether input is important enough to store. And we filter out a vast majority of this input. The sights we pass as we are driving, the sensation of scratching a bug bite, or the sound of a dog barking are not usually memories we keep for very long. 

When we are consciously trying to remember new information we receive, we store it in our short-term memory. The length of time we can retain it depends on the amount of information and its importance. Most experts believe that our short-term memories can hold no more than seven items at a time. This may be a seven-digit phone number or seven grocery items. These are not necessarily things that we need to remember for more than a little while—just enough time to make a call or take a trip to the store. 

What is Long-Term Memory?

Let’s take that phone number that you needed. After you’ve made your call, you’re not likely to remember that phone number for long. But you find yourself needing the same phone number again and again. The first several times you make the call, you’ll need to look up the number, but after enough repetitions you will have eventually memorized it. At this point you no longer need to look it up because it has transferred to your long-term memory.

This doesn’t mean that your brain will keep the phone number no matter how often you use it. While our capacity for long-term knowledge is vast, it is still limited. Therefore, long-term information that we don’t access on a somewhat regular basis will eventually fade. This is why you were able to remember algebra formulas through all three levels of courses that you took in high school and college, but now, all these years later, you can’t recall any of them. You stored them in your long-term memory when you needed them. By now, your brain has freed up that space for more pertinent information. But just like riding a bike, if you find yourself needing it again, the information will stick much more easily than when you first learned it.

How to Transfer information from Short- to Long-term Memory

When you memorized that phone number, it wasn’t because you “crammed” it. It was because you spent many short periods of time purposefully trying to remember it, over several days, weeks, or months. This is the same way students create long-term knowledge. It’s why cramming for a test might get you the grade you want, but you won’t truly have learned any of the material. Studying for 20 minutes a day every day for the week or two leading up to the test is much more effective for long-term knowledge than spending hours the night before, trying to force it all into memory. Make information stick long-term by regularly spending short periods of time working with the information. Eventually, you’ll commit it to long-term memory.