Memory

Memory is a funny and frustrating thing. We try to remember all sorts of things but then forget them or find them annoyingly on the tip of the tongue.

Multi-Store Model of Memory

Description

This is a very common model of memory that assumes there are different types of memory that are used for different tasks. In particular, these link together in an effective sequence.

Three stages of a multi-store memory are Sensory memory, Short-term memory and Long-term memory.

Sensory memory

Short-term memory

Long-term memory

Discussion

The multi-store model generally assumes memory is passive and that there are separate cognitive methods by which it is used. Thus, like a computer memory, it needs a separate processor to insert and retrieve memories.

James (1890) described a two-part model of memory, with primary and secondary storage (that equate to short- and long-term memory). Atkinson and Shiffrin (1968) describe the three-store model.

Sensory Memory Description Have you ever been in a room with people, heard your name spoken and then also realized that you can recall what was said just beforeyour name was spoken, even though you were not paying attention to this? You might even realize that you saw the person who was speaking, even though you were not directly looking at them. Or has somebody said something when you were not listening, you then said 'What did you say?' and simultaneously realize that you already know what they said? Sensory memory is a very short-term buffer where senses store what they have received before any cognitive processing occurs. Discussion Short-term sensory memory is a useful tool that allows us to pay attention to one thing whilst also being aware and able to process events in the wider surroundings after something of interest has happened. Iconic store Iconic store is where visual images are kept for a short period. It is important for our experiences as it helps us integrate our visual experience. Sperling (1960) presented three rows of four letters to subjects for 50 milliseconds. they were able to report four or five letters, but knew that there were many more. With further experimentation, he found that this visual memory lasted for about half a second. Echoic store Echoic store is where auditory senses are kept for a short period. Estimate of the duration of echoic memory range from 250 milliseconds up to a few seconds. Haptic store The haptic store in sensory memory retains physical senses of touch and internal muscle tensions. Short-term Memory Description The things that you are processing in your memory at any one time is the short-term memory. This is a limited store for things that you can think about at one time -- typically around seven. Things get into short-term memory from two directions: directly from external senses or recalled from long-term memory. 'Thinking' as an act contains much switching of items to and from long-term memory.  In a computer metaphor, short-term memory is the cache on which the processor directly acts, as opposed to the longer-term store on the disk. Items in short-term memory do not stay there by themselves and need constant attention and rehearsal to keep them in place. Without attention, they will typically remain for 20 to 30 seconds, but this can be much less (have you had someone introduced to you, then forget their name in seconds flat?). Discussion Short-term memory was described by James (1890) as primary memory (long-term memory being called secondary memory). The classic paper on short-term memory is Miller (1956), who noted that it contained 'seven, plus or minus two' slots, into each of which one chunk of information can be placed. Further research (Cavanagh, 1972) has shown that the number of slots depends on the task at hand and can be as little as three. The size of any one chunk can vary depending on the associations that it has and hence how it can be thought of as a single concept. Thus, for example, RFB may be stored as three separate chunks, whilst GOD is held as a single chunk. It is notable that newspaper columns often hold on average about seven words. This allows the whole line to be taken in at one glance without having to move the eyes horizontally. Thus you can read quickly and easily by scanning downwards only. So what? Do not try to handle too much information at once, particularly when you are learning a new subject. Remember that when you are talking to someone less expert than you about a subject, you may be able to hold complex items as a single chunks, whilst they will have to break them down -- this makes it much harder for them to process and understand what you are saying. To get others to think about more things at once, first build solid concepts that can be processed as a single chunk. Working Memory Description The working memory is a system by which conscious processing of senses and memories take place, Baddeley, A.D. and Hitch, G.J. (1974) proposed a model including a central processing executive, an articulatory loop and a visuo-spatial scratch-pad. The central processing executive has no sensory basis and is used when working with cognitively demanding activities. It directs attention, inwards or outwards, and controls cognitive processing of items in the working memory. The articulatory (or phonological) loop includes a passive store and active process that is used for such as speech processing. Words that you are going to say, for example, get rehearsed here. The scratch-pad holds dimensional information, allowing you to understand visual information. This includes placing objects relative to one another and to you. Thus a sofa may understood as being to your left side and of medium size, with a half-hidden coffee table behind it. Discussion The classic model of short-term memory has limitations in that it is simply a set of slots that take no notice of processing or sense type. This model of working model extends memory into an active, rather than passive, component, where memories and thinking are inextricably connected. So what? When working with memories, consider the impact of how it is being processed now rather than just what it is. Long-term Memory Description Long-term memory is where all of our memories are stored. If something does not reach this, then for all intents and purposes, it does not exist for us. It is one thing to have thing fall into long-term memory, but it is another to get them back out again. There are two types of retrieval:recall and recognition. Recall is where you deliberately recall something by means of thinking alone. What were you doing a week ago from today? Getting back this memory is recall. There are many types of long-term memory, including: Declarative (explicit) memory: Knowledge of facts and events. Episodic (autobiographical) memory: memories of events and periods. Flashbulb memory: memories of vivid periods. Source memory: of where and when the event occurred (often fades with time). Semantic memory: Knowledge of concepts and meaning. Prospective memory: Thoughts about the future. Procedural (nondeclarative, implicit) memory: Knowledge of how to do things. Skills and abilities. Conditioning and subconscious responses.