Who was your English teacher in 12th grade? Who is buried in Grant’s Tomb? How do you ride a bicycle? What was your favorite toy as a child? Do you know the musical score to “Grease”? To answer these questions you will have to draw upon different parts of your memory — episodic memory to recall your teacher; semantic memory for history; “procedural” memory for riding the bike; and musical memory for the score to “Grease.”
Memory is divided into three main classifications: Sensory memory, Short-term memory, and Long-term memory.
Sensory memory is what you receive from your senses — touch, taste, hearing, smell and sight. It is only held on to long enough to get passed on to short-term memory. For example: you touch the doorknob and the information is sent to the short-term memory.
.Short-term memory takes in all information produced by the senses and holds on to them for a very short period of time — as quickly as a second, or up to a couple days. It either sends this information on to the dumpster, or routes it to be held in long-term memory. “Working memory” is also referred to as short-term memory. Working memory is needed to perform complex tasks such as reasoning, comprehension and learning.
Long-term memory is lifetime memory, where we store and retrieve all the information our short-term memory passed on for us to save. It is divided into two central compartments: explicit (or conscious) memory, and implicit (unconscious) memory. From there it is further broken down into sections. The implicit memory holds the procedural memory, where the skills and tasks we perform routinely are stored. The explicit memory stores facts and events (declarative memory), which is broken down into smaller groups yet — episodic (events and experiences) and semantic (facts and concepts).
As you can see, this is just like a family tree. Each section can be broken down into subsections, and the subsections can be broken down into more categories. Somewhere in the long-term memory musical memory is stored, but scientists are still not certain if it is part of a subset, or has an individual section.
As you can see from the diagram, it is much more complex than just remembering something. The brain is wired in such a way that connections run all through the body, from the tips of our toes to the top of our head. We start out with millions of connections to the brain that thin out as we start to get older, but more and more are added all the time as we learn and utilize our brains.
When connections are damaged — like from head injuries or illness, or when they wither from age, brain cells try to find another route make new connections. If new connections cannot be made, the cells die out and the memories begin to fade.
Memory is precious, and fleeting at times. We can choose to keep them by concentration and repetition, or we can utilize memory tools that will help us retain them. Each year more research is being presented that continues to amaze neuroscientists, so the workings of the mind and our memory may never be fully understood.
As a memory expert I am constantly fascinated by the amount of information that is put out about different areas of the brain that process memory. The brain is an amazing muscle that, when exercised, can last you a lifetime.
From the Desk of Ron White
Curiosity.com — How Complex Is Memory? http://curiosity.discovery.com/question/how-complex-is-memory
The MIT Press — Lifespan Development of Human Memory: http://mitpress.mit.edu/catalog/item/default.asp?tid=9081&ttype=2