One of the most intriguing biological question is that of how exactly our brain is able to store information and retrieve it at will. Without memory, life seems to lose much of its glamour and purpose. The individual loses the ability to recognize loved ones, learn new skills, or behave appropriately in context. Memory is really what makes possible so many of our complex cognitive functions, including communicating and learning.
It is interesting to note just how closely learning is related to memory. Learning is the name given to the process by which new information is acquired by the nervous system, and memory to the mechanism of storage and retrieval of that information. Without memory, learning is next to impossible. Patients of amnesia generally find themselves unable to learn new information or use (retrieve) information that has already been acquired. Therefore, we find that memory is central to effective cognitive functioning. In fact, many believe that such a thing as "creativity" is merely the ability to retrieve various memories and put them together in differing contexts. For instance, the idea of putting peanut butter together with jelly to make a sandwich or the idea of putting a pun on words, are instances where seemingly unrelated but known memories are brought together to form novel ideas. It gives us hope therefore, that all of us are capable of achieving heights in learning and creativity by just giving a little more attention to improving memory and retention.
Memory can be categorized both qualitatively and temporally. Qualitatively, humans are said to possess two types of memory: declarative and procedural. Declarative memory is the storage and retrieval of information that is available to consciousness and that can be expressed and communicated. It consists of factual information. For instance, remembering a telephone number, a poem, or people are examples of declarative memory. Procedural memory, on the other hand, is not available to consciousness and is often involuntary. Remembering how to dial the telephone number, or how to recite the poem, or how to stroke a tennis racket are all examples of processes that are procedural, or unconscious.
Temporally, Memory falls under the categories of sensory, short-term and long-term. Sensory memory exists to provide information about sensory input, such as iconic memory (for visual stimuli), echoic memory (for aural stimuli) and haptic memory (for touch). Sensory memory is filtered into short-term memory, which then is filtered into long-term.
Short-term memory is the ability to retain information for seconds to minutes. A recent development has been the introduction of the term "working memory" which has come to replace the concept of short-term memory, and is basically any procedural memory that occurs in small time-scales. This can be any sequential act, such as searching for a lost object where one would not want to check in places that they've already checked.
Long-term memory involves the retention of information for days, weeks, months, or years. There is constant and continuous transfer of information from short to long term memory. But, to prevent the over saturation of information in our brain, an equally important phenomenon to consider is that of forgetting. Lack of use of certain concepts allows our brain to forget them and make room for more useful memories.
Scientists have seen over and over again, that good memory comes as a result of the ability to make associations, that is, give meaningless items a meaningful context. Fascinating mnemonists use this trick all the time to memorize random series of numbers and patterns, whether it be the positions on a chess board, or an eighty digit number. It is indeed the case that these chess wizards are able to understand the importance behind all of the positioning, and this association between position and meaning is what enables him/her to master the game without having to look at the board.
Let's take a look at some interesting stories of people with astonishing memories. Arturo Toscanini, the late conductor of the NBC Philharmonic Orchestra, was known for keeping the complete scores of more than 250 orchestral works in his head. So, when a bassoonist once approached him on concert night with the concern that one of his bassoon keys was broken, Toscanini immediately assured him by saying he wouldn't need it in any of the pieces they were playing that night! Another story is that of Alexander Aitken, a child prodigy, who memorized pi to thousand places, only to be beaten by an Indian mnemonist in 1981 who memorized 31, 811 places of pi, still only to be beaten by a Japanese mnemonist who took the record out to 40, 000!
Another interesting note is the fallible nature of our memory. It is very prone to guiding us away from the "truth." We tend to become so good at making associations, that they soon become false associations! Check out the exercise below to see why ...
A complex phenomenon such as memory storage and retrieval requires the use of various areas of the brain in cooperation. Though structures to function correlations have been difficult to pinpoint, many brain regions are known to be critical centers for memory. The hippocampus, located in the medial temporal lobe (middle and toward the lower portion of the brain), as well as the amygdala, thalamus, basal ganglia, cortical regions, and the cerebellum all play important roles in the different aspects of memory.
Memory, which is essential for learning, is the ability to store and retrieve information related to previous experiences. Human memory occurs in two main stages: short term and long term memory, both of which can contain declarative and procedural memories. The transfer of information from short-term to long-term memory is enhanced by: rehearsal (practice makes perfect), a favorable emotional state (confidence, alertness, and motivation), and the association of new data with data previously learned and stored in long-term memory (it's all about associations!) Studying amnesia in humans has allowed us identify brain regions that are involved in memory. The amygdala and hippocampus appear to be the central players.