LEARNING THEORY= THREE COMPONENT MODEL OF MEMORY

Three Component Model of memory
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Introduction
Aristotle considered man as a blank slate and described him as being made up of his experiences which were stored as memory. Infact memory is a process which is a sum total of encoding, storage and retrieval. After decades of research scientists have still been unable to completely understand the mechanism of human memory. Various theories have been put forward to explain how memory works. This paper will deal with the three component model of memory and also touch upon factors affecting memory.
Three Component Model
The three component model was put forward by Richard Atkinson and Richard Shiffrin (1968) and postulated that memory was a sum total of sensory register, short term memory and long term memory.

Figure 1: Schematic representation of three component model.
According to this model memory was stored in separate compartments of short term memory and long term memory, the sensory memory was added later in this model.
Sensory memory
This model considers the sensory memory as the first contact point for any stimulus perceived by sensory organs. Not all information is processed immediately and the sensory memory holds the information for a short period of time as buffer or storage tool and if attention is paid then further processing takes place. An example of sensory memory is the ability to look at an object and remember some details about it. For visual stimuli it is known as iconic memory, for auditory stimuli the term used is echoic and for touch stimuli haptic memory is used.

Short term memory
When attention is paid to sensory memory the stimulus is transferred to short term memory which can hold information for 18-20 seconds and up to 7+-2 chunks of information . To understand how STM works consider how a sentence is read, the beginning of a sentence has to be kept in mind till the full sentence is read and its meaning understood. The three component model also proposed that when attention was paid to STM it caused neural activity leading to changes in neural connectivity thus leading to storage (Irvine, 2011).
Long term Memory
The neural changes initiated in STM become permanent once long term memory is established. Its capacity is unlimited and requires consolidation to lay down changes in brain wiring. It is important to understand that mostly the so called information that we forget is a failure of retrieval mechanism and not due to loss of any information from LTM (Cahill and McGaugh, 1996).
Points in favor of three component model
The existence of memory in separate parts was proved by the case of an epilepsy patient whose hippocampus was ablated bilaterally, the patient was able to store information in STM but his LTM was impaired and no new memories could be formed.
Points against three component model
Many researchers feel that the model is too simplistic with no division in components for different stimuli. The excessive stress on rehearsal as the only mechanism of converting STM to LTM is also a point of contention.
Factors affecting memory
Fading or decay theory-
According to this concept with passage of time the neurochemical changes that are produced when new information is learned deteriorate leading to loss of information. This is applicable more to STM and occurs when the information is not used or accessed over a long period of time (Oberauer and Lewandowsky, 2008).
Interference theory-
This concept studies the interaction between the newly acquired information and the effects of past learned behavior. Proactive interference occurs causing the inability to learn new tasks due to old memories and retroactive interference causing an inability to recall old information due to newly acquired information.
Repression theory-
This concept postulates that certain memories are blocked by an individual because of trauma or stress associated with its recall. The memories may still retain their influence over the person but are not consciously recalled. This has been seen in victims of child abuse. Although conflicting research shows that such memories may be a combination of certain true and false facts.
Distortion theory-
Scientists have discovered that human memory is an extremely fragile instrument and is influenced by a variety of factors. In cases of high emotional intensity or large number of stimuli there may be incorrect processing and storage of information. Eye witness accounts are an example of this, in certain situations the testimony of the witness is influenced by the information about the incident that he receives from elsewhere and the mind uses this information to fill up the gaps in the memory that were created at the time of the incident.
Retrieval Cue Failure-
The situations where the information is stored in LTM but can’t be accessed due to lack of specific associations or a retrieval cue is called retrieval cue failure. This can be explained by the example of childhood memories which are hard to recall but if a person visits his childhood home or meets a childhood friend then the recall becomes easier because of the presence of retrieval cues that were present at the time of formation of the memory.
Effects of brain injury-
Post traumatic amnesia- In this condition there may be difficulty with memory for everyday tasks for a short duration of time after an accident.
Retrograde amnesia- In this condition there is loss of memory for events prior to the accident, may involve loss of seconds to long duration of time. The memory might return gradually in bits and pieces.
Anterograde amnesia- There is loss of memory for events after accident. The patient might not recall any hospitalization.
Important terms related to improving memory
Rehearsal-This involves repetition of information thus allowing it to spend a longer time in the STM and facilitating its transfer to LTM.
Elaboration- this involves describing facts in detail and creating additional retrieval pathways to facilitate learning.
Organization-This involves construction of categories to retain a larger amount of information.
Conclusion
The mystery of memory still remains to be solved. Extensive research is ongoing and a study of models like the three component model is a step in the long road of understanding how human memory develops and works.
Reference
Atkinson, R.C.; Shiffrin, R.M. (1968). Chapter: Human memory: A proposed system and its control processes. In Spence, K.W.; Spence, J.T. The psychology of learning and motivation (Volume 2). New York: Academic Press. pp. 89–195.
Irvine, Elizabeth. (2011). Rich Experience and Sensory Memory. Philosophical Psychology. 24 (2): 159–176.
Cahill, L.; McGaugh, J. L. (1996). Modulation of memory storage. Current Opinion and Neurobiology. 6 (2): 237–242.
Oberauer, K., & Lewandowsky, S. (2008). Forgetting in immediate serial recall: decay, temporal distinctiveness, or interference? Psychology review. 115(3), pp. 544-576.