Photo courtesy of Flickr: Clayton Cottingham
Short-term and long-term memory are needed to adequately recall and process information to be used over a longer period of time. Often, the term "working memory" is used when referring to short-term memory, although true working memory is composed of more than the simple process of short-term recall. Short-term memory typically holds a small amount of information at at time while processing that information for future use. Much as a Post-It note is designed to hold small amounts of information or a short list of items, the short-term memory typically holds seven items or less in an easily accessed state for one minute or less. Rather than processing complete concepts, short-term memory holds links, pointers, or clues to complex processes that can be recalled in long-term memory. Information in short-term memory is quickly lost unless we learn to retain it in long-term memory through a conscious effort that repeats new information, gives the new information meaning, and then successfully associates the new information with previous knowledge and understanding. Motivation also plays a part in the success of transferring information from short-term memory to long-term memory. Information that holds a strong interest to an individual is more likely to be recalled in long-term memory.
The primary area of the brain responsible for both short-term and long-term memory is found in the prefrontal cortex of the brain. Also refereed to as the central, executive part of the brain, it is this section of the brain that serves as temporary storage during the short-term memory process. It is also an important area responsible for the neural loops that recall both visual data and language. The language loop, also known as the phonological loop, is the area that makes use of the repeated sound of information to help us recall data in short-term memory. Of course, the prefrontal cortex must depend on and work with other parts of the brain to extract information for brief periods.
Short-term memory is limited to a small amount of new data at a time. Numerous research studies suggest that the number of items an average individual can recall from short-term memory is five to nine items. The number of items easily recalled depends on the characteristics or type of information available. Short categories of information or similar sounds are more likely to be retained, especially if spoken out loud several times rather than simply read. Short-term memory also has been shown to be affected by situations and circumstances taking place when the information is being presented. Distracting circumstances lessen the chance of effective recall of information from short-term memory.
In addition to repeating new information out loud when placing data into short-term memory for further processing to long-term memory, you can increase the capacity of short-term memory by using a technique known as chunking. Chunking a large amount of data into shorter groupings makes it more manageable. Consider, for example, a phone number: A hyphenated number is easier to recall than one long string of numbers without hyphens. Information held in short-term memory is easily displaced by new information or interruptions unless information is repeated and rehearsed by repeating the information out loud or attention is somehow otherwise directed to it.
Although it is generally agreed on that information in short-term memory can be transferred to long-term memory within a few seconds, how this occurs and how much information is retained permanently is still open to debate. Since the storage of information into long-term memory is intended to make information available for recall at any time in the future, it is interesting to note that many studies suggest that long-term memory decays very little over time. Even when we seem to forget things, there are those who argue that long-term memory is never truly forgotten, although we may at times have trouble retrieving information when needed. While short-term memory relies mainly on the sound of information stored, long-term memory sorts and examines information based on associations and meaning, although sound may also be a part of those associations. When we say something is right on the tip of our tongue, we usually are basing that statement on the sound rather than on the meaning of the word.
Long-term memory happens through physical changes in the neurons of the brain. The process, called long-term potentiation, is not fully understood. What is known is that when information is placed into long-term memory, circuits called neural networks are formed, strengthened, or altered. These circuits then communicate through junctions or synapses. The transfer of specialized proteins known as neurotransmitters from the synapses to receptors then communicate with various circuits in the brain when new information is reinforced. With repetition and reinforcement of new information, these special connections increase and are strengthened.
The processes of short-term and long-term memory differ both functionally and structurally. Short-term memory is dependent on transient or temporary communication in the prefrontal lobes of the brain, while long-term memory depends on neural connections throughout the brain being permanently changed. While the area of the brain known as the hippocampus is not the storage area for information, it does facilitate consolidation and transport of information from short-term to long-term memory. This transition can take as long as three months or more while permanent memory pathways are established.
Students seeking to study for the SATs or other exams can increase their chance of recalling needed information with an understanding of both short-term and long-term memory. There are a number of resources for improving memory and recall that can help improve success rates on standardized tests as well as retrieving important day-to-day information for a wide range of situations. The links below are not intended to be all-inclusive but will serve as a good sample of material available that can assist you in improving both short-term and long-term memory.