SHORT – TERM MEMORY

SHORT – TERM MEMORY

Introduction :-

Most of the time, when people think about memory they think about holding on to information for longer than a second or two. In the rest of this chapter and the next, well talk about kinds of memory more familiar to nonpsy – chologists.

Does any other distinguishing characteristic separate STM from LTM, other than length of time information is stored? Psychologists who make the distinction believe there are a number of such characteristics, including how much information can be stored, the form in which the information is stored, the ways in which information is retained or forgotten, and the ways in which information is retrieved. How psychologists working within the information processing paradigm conceptualize STM has changed a great deal over the past two decades we’ll begin with a look at the traditional description of STM before looking at a newer proposal of what has been renamed working memory to avoid confusion.

Definition :-

Short-term memory is, as just indicated, the next repository of information. First, it can be roughly identified with consciousness, second information in short term memory. Third all else being equal, information in STM will decay – will be forgotten over a period of approximately 20 seconds.

Main points of the related topic explanation; capacity :-

If you are going to store information for only a short period of time, how much room do you have in which to do so? In other words, how much information can you remember for only a brief period of time.

Chunking depends on knowledge someone not familiar with our culture might regard MTV as merely three randomly presented letters. Miller regarded the process of forming chunks as a fundamental process of memory – a very powerful means of increasing the amount of information we can process at any given time, and one we use constantly in our daily lives. The process of chunking can be seen as an important strategy in over coming the severe limitation of having only seven or so slots in which to temporarily store information.

Coding :-

The term coding refers to the way in which information is mentally represented that is, the form in which the information is held. When you try to remember a phone number as in the preceding example, how do you represent it? A study by R. Convad addressed this question. He presented participants with lists of consonants for later recall. Although the letters were presented visually participants were likely to make errors that were similar in sound to the original stimuli. So, if a p had been presented, and participants later misre called this stimulus, they were much more likely to report a letter that sounded like p (for example G or C) than to report a letter that looked like P (such as F). Remember, the original presentation was visual, but participants apparently, were confused by the sound participants were apparently forming a mental representation of the stimuli that involve acoustic rather than the visual properties.

Retention Duration and Forgetting :-

We regard STM as the storage of information for short periods of time. But how short is short? John Brown (1958) and Peterson and Peterson (1959), working independently, came to the same conclusion : If not rehearsed, information is lost form STM is as little as 20 seconds that length of time is called the retention duration of the memory.

Retrieval of Information :-

We’ve talked about the ways in which people hold onto information for brief periods of time : how they encode it, how much they can encode, and how long they can retain it. That brings us to the question. “How do we retrieve this information from STM when we need it again”.

Sternberg’s first question was whether we search for information held in STM in a parallel or a serial manner.

If you compare Titanic simultaneously to all the titles on your list, you are performing a parallel search. Essentially, no matter what the number of titles is, you examine them at the same time, and it takes you no more time to compare Titanic to 1 title than to 10 tides. Figure 5-6 (A) depicts how the data would look if you used parallel search, plotting time to search against memory set size.

Suppose, instead, that you use a serial search. In our movie titles example, this would mean comparing Titanic to the first movie title on the list, then to the second title on the list, and so on, until you come to the last title. The comparisons are done one at a time. In this model, the longer the list is, the longer it should take to decide it Titanic matches a title on that list successful searches are indicated by the “yes” line; unsuccessful searches by the “no” line.

Another kind of serial search is an exhaustive search, meaning that even if a match is found, you continue looking through every other item in the set. In our example, this would mean that even after you find Titanic, you check the remaining titles on the list with this kind of search, it takes just as long for successful as for unsuccessful searches. Figure 5-6 (c) shows this possibility.

Working Memory :-

The idea memory consists of a number of information – processing stores was most completely described by Atkinson and Shiffrm (1968). These authors distinguished between the information being stored, calling this “Memory”, and the structure that did the storing, which they termed a “store”.

Baddeley (1981, 1986, 1990) conceived of WM as consisting of three components as depicted in the first in the central executive. This components directs the flow of information, choosing which information will be operated on when and how. Researchers assume it has a limited amount of resources and capacity to carry out its tasks. Some of this capacity can be used to store information. The central executive is thought to function more as an attentional system than a memory store, meaning that rather than dealing with the storage an retrleval of information, the central executive deals with the way resources are allocated to cognitive tasks. So the central executive would be the system that controls many of the phenomena reviewed in chapter – 4.

The two other components of Buddeley’s model are concerned with the storage and temporary maintenance of information : the phonological loop, used to carry out subvocal rehearsal to maintain verbal material, and the visuospatial sketch pad, used to maintain visual material through visualization. Researchers think the phonological loop plays an important role in such tasks as learning to read, comprehending language, and acquiring vocabulary. The visuospatial sketch pad involves the creation and use of mental images.

References :

Cognitive Psychology perception, Attention & Memory Kathleen M. Galotti