Memory
Information-Prossessing Theory
Cognition refers to the processes through information coming from the senses is transformed, reduced, elaborated, recovered, and used. The term 'information' refers simply to sensory input from the environment that informs us about something that is happening there. Cognitive processes are thus the mental processes involved in knowing about the world; as such they are important in perception, attention, thinking, problem solving, and memory.
The branch of psychology that deals with cognitive processes is known as cognitive psychology, and the modern-day study of memory, since it emphasizes the mental processes involved in storing information and retrieving it from memory, is a part of cognitive psychology.
Three distinct processes of memory have been identified. Those are (i) an encoding process, (ii) a storage process, and (iii) a retrieval process.
(i) Encoding is the process of receiving sensory input and transforming it into a form or code which can be stored.
(ii) Storage is the process of actually putting codded information into memory.
(ii) Retrieval is the process of gaining access to stored, codded information when it is needed.
☆INFORMATION PROCESSING THEORY☆
A computer takes items of information in; processes them in steps or stages; then produces an output. Models of memory based on this idea are called "Information- Processing theories". A number of such models of memory have been proposed. One of the most prominent and influential of these models is "The Information Processing Theory" developed by Richard Atkinson and Richard Shiffrin (1968).
In the Atkinson- Shiffrin theory, memory starts with a sensory input from the environment. This input is held for a very brief time --- several seconds at most --- in a sensory register associated with the sensory channels like vision, hearing, touch, and so forth. Information that is attended to and recognized in the sensory register may be passed on to short-term memory (STM), where it is held for perhaps 20 or 30 seconds. Some of the information reaching STM is processed by being rehearsed --- that is having attention focused on it, perhaps by being repeated over and over, or perhaps by being processed in some other way that will link it up with other information already stored in memory. Information that is rehearsed may then be passed along to ling-term memory (LTM). Information not so processed is lost. When items of information are placed in LTM, they are organized into categories, where they may reside for days, months, years, or for a lifetime. When we remember something, a representation of the item is withdrawn, or retrieved from LTM.
● The Sensory Register :- Information can be held for a very brief time in the sensory channels themselves. This storage function of the sensory channels are called 'sensory register'. Most of the information briefly held in the sensory register, is lost; what has been briefly stored simply decays from the register. However, we pay attention to and recognize some of the information in the sensory register; when we do this, the attended-to information is passed on to STM for further processes.
● Short Term Memory (STM) :- A number of experiments have shown that short-term memory can be distinguished from long-term memory. STM is memory that holds information received from the sensory register for up to about 30 seconds, although the length of the retention depends on a number of factors.
STM also has a very limited storage capacity. This capacity is estimated to be about 7 items, plus or minus 2 (Miller, 1956). The storage capacity of STM can be increased, however, by a process known as 'chunking'. Most of us have learned to combine several items into a 'chunk' as we receive them; then we can retain several (7 +/- 2) of those 'chunks' of information in our STM.
Since the capacity of this memory storage is so small, much information stored here is lost because it is displaced by incoming of information. Before it is lost, however, some of the information can be retrieved and used. Studies of retrieval from STM show that we rapidly scan through STM when searching for an item of information. A surprising feature of this scanning process is that we examine everything in STM when we are trying to retrieve an item from it; the scanning has been found to be exhaustive. Instead of stopping when the search-for item is located, the scanning process continues until all of STM has been examined. Then, if the item was found during the exhaustive scan, it is retrieved. Some of the information in STM is neither lost nor retrieved but passed along to the next memory storage --- LTM, through rehearsal.
● Rehearsal: - The process of rehearsal consists of keeping items of information in the centre of attention, perhaps repeating them silently or aloud. The amount of rehearsal given to items is important in the transfer of information from STM to LTM. In general, the more and item is rehearsed, the more likely it is to become part of LTM. However, in the last few years, other experiments have indicated that the sheer amount of rehearsal may be less important than the ways in which the information is rehearsed. Just going over and over what is to be remembered (called 'maintenance rehearsal') does not necessarily succeed in transferring it to LTM. What is known as 'elaborative rehearsal' is more likely to succeed. Elaborative rehearsal involves giving the material organization and meaning as it is being rehearsed; it is an active rehearsal process, not just the passive process of repetition. In elaborative rehearsal, people use strategies that give meaning and organization to the material so that it can be fitted in with existing organized long term memories. Elaborative rehearsal is a part of an alternative conception of memory called the 'levels-of-processing theory'; it also relates to the organization of memory and to what is called 'semantic memory'.
● Long - Term Memory (LTM) :- The time span over which information can be stored in LTM cannot be stated very precisely. Long -term memories may last for days, months, years, or even a lifetime. Also unlike STM, the storage capacity of LTM has no known limit.
Some theorists believe that there is no true forgetting from LTM. According to this view, once information is stored in LTM, it is there for good; when we seem to forget, it is because we have trouble retrieving, or getting access to, what has been stored. In other words, the information is still there; we just cannot get it because it has not been stored in an organized fashion or because we are not searching for it in the right part of the memory storehouse.
LTM contains words, sentences, ideas, concepts, and the life experiences we have had. Two different but related LTM stores are said to exist. One called "semantic memory" ('semantic' refers to 'meaning'), contains the meanings of words and concepts and the rules for using them in language; it is a vast network of meaningfully organized items of information. The other, containing memories of specific things that have happened to a person, is called "episodic memory".
■ THE LEVELS-OF-PROCESSING THEORY:-
Information is transferred from stage to stage until some of it is finally lodged in LTM. A contrasting model of memory involves what are called "levels of processing" (Craik & Lockhart, 1972), with more recently, the idea of elaboration added to the "levels-of-processing framework" (Craik & Tulving, 197t).
According to the levels-of-processing idea, incoming information can be worked on at different levels of analysis; the deeper the analysis goes, the better the memory. The first level is simply 'perception', which gives us our immediate awareness of the environment. At a somewhere deeper level, the structural features of the input (what it sounds like or looks like, for example) are analysed; and finally, at the deepest level of processing, the meaning of the input is analysed. Analysis to the deep level of meaning gives the best memory.
Rehearsal plays a role in the deeper processing of information. According to the levels-of-processing view, simply repeating the information (maintenance rehearsal) is not enough for good memory. All this does is maintain the information at a given level of depth; for deeper levels to be reached, the rehearsal must be elaborative. In other words, rehearsal must process the information to the meaning level if the information is to be well retained. Rehearsal thus seen as a process which gives meaning to information.
The idea of elaboration has been added to the levels-of-processing theory. Elaboration refers to the degree to which incoming information is processed so that it can be tied to, or integrated with existing memories. The greater the degree o elaboration given to an item of incoming information, the more likely it is that it will be remembered.
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