What makes Difficulty of maintaining even Small amount of Information in the Memory over a short period of time?

How many times have you been introduced to a small group of people and as soon as the introduction is Completed you turn to the first person introduced and simply cannot remember the person’s name?

Equally frustrating is the experience of obtaining of telephone number from Directory Assistance and having no pencil or pen to record the number. What do you do?

Usually, most of us repeat the number repeatedly until dial it, but if anyone talk to us we even think of something other than the number before it is dialled, we must make another call to Directory Assistance. 

These two common examples illustrate the surprising difficulty of maintaining even Small amounts of information over a short period of time. 

What makes this difficulty interesting is the contrast with remembering your best friend’s name or your own phone number, things you are unlikely to forget even if it has been some time since you thought about the them. How are we to explain the difference in these two situations?

Psychologists begin their answer to the question by making a distinction between short term and long term memory. But these terms are just labels that describe the fact that some information is retained for a short time while other information is retained for a long time. 

The real question is, what are the psychological processes that cause this difference in retention? 

Richard Atkinson and Richard Shiffrin proposed a view of the entire memory system in 1968. According to their model, incoming information flows from the Sensory register or sensory memory to short term memory to permanent storage in the long term memory. The transfer of information from the sensory register to the short term memory is controlled by attention. Once in short term memory, the information is subject to control process these are operations serving a variety of memory functions. The most important control process is rehearsed. Rote or maintenance rehearsal, functions primarily to keep information active in short term memory. Maintenance rehearsal corresponds to simple repetition of information. Elaborative rehearsal involves relating the information to other known information, a process involving meaning. For example, if words dog, tree and cat are to be remembered, elaborative rehearsal might involve the construction of a relationship among the words even to forming a visual image of a dog chasing a cat up a tree. Elaborative rehearsal functions to quickly transfer information to long term memory. Rehearsal is important because the model assumes that information decay quickly from short term memory unless it is actively used. Other control processes include coding, which involves attaching appropriate information from long term memory to the short term information. For example a telephone number easier to remember if it is coded into larger units than dealt with as single digits: 918777439176 becomes 91,877,743,91,76. The smaller number of large chunks allows more frequent rehearsal of the information. The rules for transforming the single digits into larger chunks are retrieved from long term memory and applied to the string of single digits in short term memory. The ultimate function of the control process is to combat the effect of decay.

The strategies for retrieving information from long term memory are another important short-term memory control process. For example, if you are asked the question, “who was the second President of India?” your strategy may be to activate long term information concerning “names associated” with the psychology of attention. These names are then brought to short term memory where you decide which is the correct answer. An important feature of the Atkinson and shiffrin model is that the short term memory system has a severely limited capacity. This implies not only that a small number of items can be stored, but also that the control process require some of the limited capacity. Rehearsal, for example, may guard some information against loss from short term memory, but this gain comes at the expense of not being able to rehearse other items. Chunking smaller units into larger units requires capacity that then cannot be devoted to storage or rehearsal of other items. In general, the contract processes expedite the processing of some information, but this facilities comes at the expense of other information. 

There are three basic characteristics to distinguish short-term memory from long-term memory: forgetting is due to decay of trace; the capacity for storage is small; and the trace is phonetic code.

Rapid Decay of the Trace. In Brown Peterson paradigm (Brown in England and Peterson in the United States) experiment results are the rapid forgetting that occurs over the very short retention interval. After 18 seconds, only about 10% of the material is remembered. Such a poor memory after such a brief period of time was a starting finding that served as one basis for claiming a separate, short duration memory system.

Capacity of Short Term Memory. Immediate memory span is measured by presenting a list of items, digits, letters, or words and determining how many items can be recalled in their correct serial order immediately after presentation. Miller noticed that most people remember between five and nine items, which suggested that short term memory has quite limited capacity.

Phonetic Code. A phonetic code in short term memory makes sense because rehearsal requires a code that is easily repeated. Sound patterns satisfy this requirement, and therefore, a phonetic code in short-term memory becomes highly adaptive.

Whether short term and long term memory occupy different location in the brain, we can now see that the answer appears to be both yes and no. Information in short term memory is really just information stored in long term memory that is under active consideration by conscious processes. This conclusion is consisted with William James view that short term and long term memory do not reflect different places or systems but, rather, reflect a difference in the activation level of information in long term memory. What neural studies have added is the finding that the brain areas responsible for initiating and maintaining this active state are located in the frontal lobes.