Short-term memory acts as a kind of buffer between sensory memory and long-term memory. You can think of short-term memory as similar to RAM in a computer. It holds information for quick access for a short period, while long term memory is like the hard drive, where information is stored long term.
You can also think of short-term memory as the brain's scratch pad, where things are written and erased frequently. The amount of information short-term memory can hold varies but is rarely higher than seven items without special training to strengthen it. By using the methods in this book, you will be able to strengthen short-term memory, giving you a larger scratch-pad to work with.
As time goes on, the aging process, certain medical conditions, and simply not having a brain-healthy lifestyle can diminish the capacity of short term memory, which can make it more difficult for information to be moved to long-term memory storage. Maintaining a healthy lifestyle is imperative to maintaining a healthy memory, be it short term or long term.
Long Term Memory
Long-term memory is quite different and significantly more complex than both sensory and short-term memory. Going back to our analogy of a computer, long-term memory is much like the hard disk, where things are stored permanently, to be accessed when needed, not temporarily. There are a number of types of long term memory, some of which are not fully understood. We will look at two here, explicit and implicit memory .
Explicit memory
Explicit memory refers to recollection of experiences. It works like a replay of experiences from the past. Explicit memory recollection is done both consciously and intentionally.
There are several types of explicit memory. One of these is episodic memory, which consists primarily of the recalling of situations and events from a persons life. Interestingly, these memories do not need to be things that happened to the person remembering them, but can also be things that happened near them and were significant. Whenever you reminisce about your past, your brain is going through its collection of episodic memories.
Implicit Memory
Implicit memory is a form of memory that is retrieved and used unconsciously, as opposed to explicit memory, which requires a conscious effort to retrieve. As a concrete example, take driving lessons. When you take a written test about driving, you are using explicit memory to recall the answers to the questions on the test, while the improved driving skill because of the lessons is an example of implicit memory.
Procedural Memory
Procedural memory is one type of implicit memory that allows us to perform tasks we have learned how to do without specifically thinking about them. It consists of things we have learned to do automatically, like riding a bicycle or eating. Although we can do such tasks without even thinking about them, it is often difficult to explain exactly how we do them. When a person gets amnesia, despite forgetting much or even all of their personal life, they often keep procedural memory and can still function normally in many ways despite having no memory of the past.
Priming
Implicit memories are also generated through a process known as priming. The brain is "primed" by experiences; so if you have heard something very recently, or many more times than another thing, you are primed to recall it more quickly.
As an example, if you were asked to recall an animal with a name beginning with the letters Ca, you would most likely answer cat, unless there was some close connection in your mind to a different animal that started with the same letters, such as a canary. A second example would be to recall your favorite food, song, or movie.
Lifestyle Choices That Can Improve Memory
A holistic approach is the best way of improving your memory. Your cognitive functioning is affected by just about everything about you: your physical and mental state, what you eat, what kind of environments you live in, your sleeping patterns, and even what kinds of recreation you indulge in. In this chapter, we will look at some of the lifestyle changes you make that can improve your memory.
Exercise and Memory
We all know that exercise is a necessity for sound physical health. The dangers of a sedentary lifestyle include problems as diverse as obesity, a weakened immune system, and cardiovascular disease. The beneficial effect of exercise on memory has also been demonstrated in study after study, especially for older people. Studies of people with mild cognitive impairment showed that their memory noticeably improved after resistance training (weight lifting and other strength-building exercises), and even more after aerobic exercise. Exercising regularly can benefit memory indirectly by increasing lung capacity and blood circulation, thus delivering more oxygen and sugar to the brain.