Study Design Dot Point: Comparison of models for explaining human memory The Atkinson-Shiffrin Multi-Store Model of Memory A model of memory is used to represent, describe and explain memory, its components and processes. Often diagrams are used to represent the movement of information from one store to another. A Diagram of the Atkinson-Shifrin Model You should be able to visualise this model in your visuo-spatial sketchpad and reproduce it at will! According to the Atkinson-Shiffrin model, memory has three components. Each stores, encodes and processes information in varying ways: • the sensory register Sensory information that is not attended to is lost for ever. Information attended to in this register passes to ... • the short-term store Holds limited information from the sensory register and information retrieved from the long-term store. Rehearsal allows storage in ... • the long-term store Permanently held information, in a store with essentially unlimited capacity Structural features of the Atkinson-Shiffrin Model ❖ This means the permanent, built-in or fixed features of memory ❖ Structural features include: ❖ the three different stores ❖ the function of each store - that is, the role it plays in human memory ❖ each component’s storage capacity ❖ the duration of time that information is held Control features of the Atkinson-Shiffrin Model ❖ These vary from individual to individual - we can choose. ❖ For instance, you can choose what you pay attention to and therefore what passes from the sensory register to the short-term register ❖ Rehearsal is also under individual control; it determines how long information is held in the short-term store and whether it is passed on to the long-term store ❖ Retrieval is another control process. The method we use to access information is chosen by us. ❖ SUMMARY: The Atkinson-Shifrin Model is based on and supported by substantial research. It is still useful in understanding memory, but it has been developed and challenged. ❖ There are now believed to be several sensory registers, possibly one for each sense. ❖ Short-term memory is now considered to be more complex than it was believed to be by Atkinson and Shriffrin. It is now seen as a number of separate, interacting components, not a single store. ❖ Long-term memory is no longer seen as one system, but as several sub-systems or stores - procedural (implicit), declarative (explicit), which includes episodic and semantic, etc. There is more focus now on how we not only retrieve memories but reconstruct them in the process. Criticisms of the Atkinson-Shiffrin Model ❖ The concept of the sequenced flow of informaon through sensory, STM and finally LTM is now believed to be more complex than proposed by Atkinson and Shiffrin. Some believe this model was too straighEorward and linear in its descrip5on of memory processes. ❖ There is now evidence for the concept of a separate sensory register for auditory informaon and for other senses. Limitations of Atkinson and Shifrin’s Concept of STM: ❖ Neuroimaging techniques have matched STM and other A PET scan showing the stores with physical loca:ons active brain of a person in the brain, demonstrang doing a STM task that STM is much more complex than Shiffrin and Atkinson realized. ❖ The Atkinson-Shiffrin model tended to overemphasise the See the discussion of Baddeley role of maintenance rehearsal and Hitch’s Working Memory Model for the source and and overlook elabora:ve meaning of this scan. rehearsal. Limitations of Atkinson and Shifrin’s Concept of LTM: ❖ LTM is now believed to have different subsystems, such as episodic and procedural; each of these processes and stores different kinds of informa:on. ❖ The role of implicit memory is perhaps not emphasised adequately in this model. ❖ Informaon is not always simply retrieved from LTM and available for use exactly as it was originally stored; it has been shown that we reconstruct memories, that is, fuse a remembered event with newer informaon, changing the “memory” subtly in the process. More about Sensory Memory the first store of memory is fleeting in d u r a t i o n, but h u g e in capacity Be careful not to confuse these two concepts of duration and capacity! Duration versus Capacity • Duration means the length of time that the memory is held in a memory store • Capacity means how much can be held at any one time SENSORY MEMORY is brief or fleeting in duration but virtually unlimited in capacity Iconic Echoic memory memory Examples of sensory registers Sensory Memory holds an exact copy of sensory input has a register for each sense the two registers that have been most extensively researched are: ECHOIC ICONIC ECHOIC MEMORY Brief auditory memory which lingers for 3-4 seconds This is long enough for us to be able to link impressions of sound with the next syllable or word we hear When we pay attention to the sounds (in order to transfer them to short-term memory) we are able to make sense of the sounds as a word or the words as a sentence Echoic memory thus makes speech perception possible ICONIC MEMORY STORE FOR VISUAL SENSORY INFORMATION: Even more fleeting than echoic memory, this sensory register holds a vast amount of visual information for about a third of a second. Your text says - 0.2-0.4 of a second. Sperling’s studies showed that people actually held all the information he projected on a screen, but lost it faster than they could report it. To overcome this difficulty, he devised a research method that demonstrated both the vastness and the briefness of this memory store. MOVING TO THE NEXT STAGE: Sensory memory is huge in capacity, but fleeting in duration. One advantage of this is that we can quickly filter out extraneous matter. We don’t have to remember everything we see, hear and experience. In fact, it would be overwhelming if we did. The only way we can keep, hold on to, preserve and hope to prolong sensory memories is through ATTENTION. Only the material we attend to passes into short-term memory. The usefulness of sensory memory in allowing us to filter out overwhelming detail... How could you cope with life if you couldn’t filter out the extraneous details? Short-Term Memory temporary storage (18-20 seconds without rehearsal) (Note that Atkinson and Shiffrin believed this period was 30 seconds in their model. See your text, p.304, under DURATION OF STM for clariOication of this point.) limited capacity (7 plus or minus 2 bits or chunks) often encoded phonentically (according to sound) very sensitive to interference information is lost though decay (fading) or displacement (being pushed out by new information) The distressing shortcomings of STM For instance, as a youthful sales assistant in the shoe department at Myer, I would be asked by three different customers to get an 8 in the style Ecstasy by Jane Debster, a 7 in Cargo by Sandler and a 40 in 19203 by Stuart Weitzmann. Should I have been able to hold this amount of information in my STM? Yes! That’s actually only 6 pieces of information, chunked (or 9, if you count the brands). I would enter the rabbit burrows of the back of the department, muttering to myself (maintenance rehearsal, vocal or sub-vocal). Then the manager would say, “Roslyn, can you work tomorrow from 5-9 and on Saturday from 1-5?” “Sure I can!” I would cry. Then I would realise that I could no longer remember which size I needed to get in which shoe. I would have to go out and say to the customers: “I’m sorry. I am an idiot and have forgotten what you asked for.” What I really said: “Forgive me, although I had successfully chunked your request for shoes and was rehearsing it to keep it in my short-term memory until I found what you wanted, my maintenance rehearsal was interrupted and the information in my STM was consequently displaced. It’s not my fault, it’s a well-known psychological phenomenon.” Increasing the capacity of STM through chunking Extending time in STM OR moving material into LTM: Rehearsal: Any activity that allows information to be retained in memory and retrieved when required: may be verbal, vocal, non-verbal, sub-vocal, mental imagery. Maintenance rehearsal: Simple, rote repetition of information. This needs to be attended to consciously – should not just be meaningless repetition. Elaborative rehearsal: Involves linking new information in a meaningful way with information already stored in long-term memory. More active and more effective than maintenance rehearsal, this ensures that information is encoded well. Elaborative Rehearsal Any activity that adds meaning to information allows it to be encoded Using a diagram allows elaborative semantically, which is how LTM is rehearsal of a organised. concept. For instance, self-referencing is a form of elaborative rehearsal. You tie new information that you need to learn to something that is personal and meaningful to you, as I did with my shoe example. Well-encoded information is easier to retrieve because there are many ways in which you can access it in your long-term memory. Elaborative Rehearsal More Elaborative Methods Work out an analogy, a rhyme, an acrostic, a story, to help you remember something. Think of examples, work out synonyms you could use to describe a concept, change a teacher’s description into your own wording, draw a concept map, a diagram, a picture or set of symbols. The more you work on the information, the easier retrieval will be. On the neuronal level, there will be more connections between neurons that will increase the efficiency of communication in your brain.