Multistore model of memory

• Memory consists of three stores: a sensory register, short-term memory (STM) and long-term memory (LTM) according to the multistore model.
• Information is detected by the sense organs and enters the sensory memory.
• If attended to, the information enters the short-term memory.
• Information from the short-term memory is transferred to the long-term memory only if that information is rehearsed (i.e. repeated).
• If maintenance rehearsal (repetition) does not occur, then information is forgotten, and lost from short-term memory through the processes of displacement or decay.
• One strength of the multistore model is that it gives a good understanding of the structure and process of the short-term memory (STM), allowing researchers to expand on this model and conduct experiments to improve it.
• The multistore model can account for primacy & recency effects.
• The model is supported by studies of amnesiacs, such as the HM case study.
• The multistore model is oversimplified, in particular when it suggests that both short-term and long-term memory each operate in a single, uniform fashion.
• Both short-term and long-term memory are more complicated than previously thought, with different types of long-term memory identified, namely episodic (memories of events), procedural (knowledge of how to do things) and semantic (general knowledge).
• Rehearsal is considered a too simple explanation to account for the transfer of information from short-term memory to long-term memory.
• The main emphasis of the multistore model is on structure and tends to neglect the process elements of memory, focusing on attention and maintenance rehearsal.
• Elaboration rehearsal, which involves a more meaningful analysis of information, leads to better recall than just maintenance rehearsal.
• The multistore model has been criticized for being a passive/one way/linear model.
• Short-term store (STS) - holds information for up to 20 seconds, can be consciously rehearsed to maintain it
• Sensory register (SR) - temporary storage of sensory input from our environment, lasts only a few seconds
• Long-term store (LTS) - unlimited capacity but limited accessibility, divided into two parts: explicit (declarative) and implicit (non-declarative)
• Encoding: activities taking place during presentation of TBL information (study phase).
• Storage: activities taking place during the study-test interval.
• Retrieval: activities taking place when stored information is utilized (test phase).
• Encoding I: bringing information processing to bear on information.
• Encoding II: utilizing the fruits of Encoding I as a means for transferring information from STM to LTM.
• Examples: elaborative rehearsal, semantic association, imagery, other strategies.
• The Multi-store Model of Memory: Atkinson & Shiffrin (1968).
• Sensory Store: highly accurate, rapidly decaying buffer that contains more information than we normally report on, but lost quickly.
• Proposed Properties of STS: Limited Capacity (digit span, recency measures), Coding (material specific: acoustic, visual), Forgetting from STS (Decay).
• Evaluation Of Multi Store Model of Memory: Most assumptions are incorrect or can account for only a part of the data, can’t account for patients with intact LTM with impaired STM, oversimplifies the roles of proactive interference and of retrieval cues in short-term memory and forgetting.
• Forgetting from LTM: Mechanisms (Poor encoding, levels of processing account, interference, decay), Encoding specificity.
• Working Memory: A system which keeps a representation of information active and “on line” for immediate future use (short-term memory), involves the “temporary storage and manipulation of information that is assumed to be necessary for a wide range of cognitive functions”, demands: storage vs manipulation.
• Features of the Phonological Loop: Two features: Phonological store (Auditory presentation of words has direct access, Visual presentation only has indirect access), Articulatory process.
• Evaluation of the Evidence for the Phonological Loop: Accounts for phonological similarity and the word-length effect, support from neuroimaging studies, its function may be to learn new words, also probably important in aspects of language comprehension.
• Visuo-spatial Sketchpad: Used in the temporary storage and manipulation of spatial and visual information, Baddeley et al (1975), the pursuit rotor task-impairs performance on location visualization task, Logie (1995), Visual cache – form/color (ventral?), Inner scribe – spatial and movement (dorsal?).
• Evaluation of the Visuo-spatial Sketchpad: Supported by imaging research that shows the independence in spatial and visual tasks, consistent with ventral-dorsal visual pathway concept, support from studies of brain-damaged patients, many tasks require both components, not clear how information is combined and integrated.
• Central Executive: Baddeley (1996, p 6) admitted “our initial specification of the central executive was so vague as to serve as little more than a ragbag into which could be stuffed all the complex strategy selection, planning, and retrieval checking that clearly goes on when subjects perform even the apparently simple digit span task.”
• Concept of central executive has evolved as an attentional system, Baddeley (1996) identified the following functions: switching of retrieval plans, timesharing in dual-task studies, selective attention to certain stimuli while ignoring others, temporary activation of long-term memory.