Memory Weeks 1 and 2 The story so far… ENCODING Evidence? DURATION Evidence? CAPACITY Evidence? Sensory Memory By Sensory modality. • S.T.M. • L.T.M Acoustically Semantically (sometimes visual) SPERLING BADDELEY BADDELEY ½ - 2 secs 18 – 30 sec Life time? SPERLING Very limited SPERLING PETERSON & PETERSON 7 + or - 2 Infinite? MILLER Encoding / Storage / Retrieval Cognitive Approach Memory: the storage and retrieval of information Computer analogy – human memory is like a computer; it allows us to process and store information for later use Encoding (transform the info so it can be stored – visual, acoustic, semantic) Storage (holding onto the information) Retrieval (bringing the memory out of storage) One of the most widely accepted theories of memory is the Stage Model of Information Processing the model proposes that information is processed and stored in 3 stages information is stored in multiple locations throughout the brain in the form of networks of connections Stage theory of Memory (cognitive approach) Multi-Store Model Atkinson and Shiffrin (1968) ! Remembering . . . For us to remember a piece of info well, we need to: Pay attention to it This gets it from the SM to the STM Rehearse it Maintenance rehearsal keeps it in our STM Elaborative rehearsal can get it to our LTM Multi-store Model Atkinson and Shiffrin (1968) Echoic Store Iconic Store Evidence? As a group discuss the evidence to support this model Find at least one piece of evidence for each store – all the answers are in your memory booklet, page 4 Use other texts to expand your knowledge of these studies SM : •set of limited capacity, modalityspecific stores (eg vision, sound) •Duration: BRIEF period (1-2 s). •Info is unprocessed. •Info is passively registered – i.e. we cant really control what enters Echoic Store Multi-store Model Atkinson and Shiffrin (1968) Iconic Store STM : •Capacity: limited (about 7) •Duration: Very limited (18secs) •Encoding: acoustic (sound) LTM •Capacity: unlimited •Duration: unlimited (lifetime) •Encoding: semantic (meaning) Further research that supports the MSM Experiment by Sperling (1960): – Presented a grid of letters (3 rows ) for 50ms – People recalled average: 4 letters but were aware there were more. – That was called whole report technique – Sperling then used “partial report” technique… – Showed chart for 50 ms then AFTER played 1 of 3 tones – High tone = they had to recall top row – Medium tone = they had to recall middle row – Low tone= had to recall bottom row. – They could recall average of 3 letters from the correct row. – …showed that iconic memory held up to 9-10 items! Duration: – Info decays within about 2 secs (or less) Further evidence for distinction between STM & LTM Funny Serial Position Effect: Test Careless Hospital Beef Mug Aspect Business Check Models Percentage Life Television Job Elbow Water Primacy Recency Condition 1: found the expected serial position curve. Condition 2: •found the distracter task had disrupted the recency effect – so the last few words were displaced from the STM & not well recalled. •The first few words were NOT affected as they had been rehearsed & so had passed into the LTM. • EVIDENCE that the STM & LTM are separate stores.. • EVIDENCE that rehearsal pushes info from STM to LTM Individual Activity – no notes please • On a piece of A4 paper, draw the model • Add the names of research that provide evidence of each stage Evaluation the Model • Below, bullet point 2 strengths &of 2 limitations of the model Multi-Store Model (stage model) Strengths • Useful in memory research – provides the foundations for future research • Good supporting evidence: SM (Sperling 1960); STM (Miller 1956, Peterson&Peterson 1959, Baddeley 1966); LTM (Bahrick 1974, Baddeley) • Primacy & Recency effect shows separate stores (Glanzer & Cunitz, 1966) • Korsakoff’s Syndrome (amnesia due to chorionic alcoholism). People with this can recall last items on a list (suggesting unimpaired STM) but struggle with first items (suggesting LTM is poor) MSM Weaknesses REHEARSAL is central to MSM but there is lots of evidence to suggest that this is the worst way to pass on info…meaning is the best way to learn • Kulik & Brown: “flashbulb memory” where highly emotional, shocking events (eg.9/11) go into LTM with NO rehearsal. Atkinson & Shriffin thought info flows from STM to LTM (one way!) & has to be processed by STM before getting to LTM. BUT in order to identify letters “B,D,G “ etc – you need to get stored information from LTM that B makes the sound “bee” = not 1-way MSM suggests 1 LTM store, but evidence from amnesia patients indicates different LTM stores • Tulving 1972 identified 3 stores • Semantic (knowledge of world/words) Episodic (what you did yesterday/last week) Procedural (doing things e.g play music) Types of Long Term Memory Procedural Semantic Episodic Our “how to” memory, e.g: riding a bicycle we may not be able to explain it in words or even know that we have this memory. Little research has been done on this. Our “know that” memory, e.g: capital of France because it is processed by meaning it is organised in the way it was originally learnt. Most memory research has looked at this. Our “episodes of life” or autobiographical memory, e.g: last holiday, 18th birthday. Includes Flashbulb Memories which are vivid, emotive memories – ( eg 9/11 ). Working Memory Model (cognitive approach) Another model that illustrates the cognitive approach is Working Memory Model by Baddelely & Hitch 1974 The model looks at the functional components of cognition that allow humans to comprehend their immediate environment It also proposes how humans retain information about their past experience, which can then support the learning of new knowledge, problem solving and achieving goals Agreed with MSM (stage model) that A & S proposed but felt that a single STM store wasn’t sufficient One STM store couldn’t account for everything that memory could do B & H thought that STM must have more than one component Working Memory Model How did they test it? Baddeley & Hitch asked ‘what is STM for?’ Experiment time!!! Lets try it - groups of 4 please 2 participants & 2 experimenters Participants leave the room please Experimenters: 1 timer/recorder; 1 reader This procedure must be carried out in a quiet space – use canteen, corridor, photocopy area, stairwell …. How did they test it? They devised the ‘dual task technique’. Participants were asked to perform a reasoning task and at the same time recite aloud a list of six digits or repeatedly saying ‘the the the’. Performance was then compared to when the reasoning task was done on its own. What did they find? The speed of answering the true/false to the verbal reasoning task was slower when having to do another task (e.g. say ‘the the the’ repeatedly) than when just focusing on the task alone. Average time taken to solve verbal rehearsal Control group 2.79 ‘the, the, the’ 3.13 ‘1, 2, 3’ 3.22 Random six-digit number 4.27 Conclusion: The STM must have more than one component and must be involved in processes other than simple storage e.g. reasoning, understanding and learning, perception Clearly a cognitive approach underpins this model! What is working memory? Focuses on STM and sees STM as much more active than SM and LTM. It is what we are using all the time when we are thinking about things and trying to learn new information The information may come in two sources e.g. new sensory info and existing info stored in LTM For example, if you were drilling a hole using a power drill, you would use new sensory information to place the drill over the area you wished to drill the hole and existing information about how to use the drill You can illustrate working memory by asking how many windows in your house? 3 main components to STM: • Central Executive (the supervisor) • The phonological loop (the inner voice) • Visuo-spatial sketchpad (the inner eye) Working Memory Model Baddeley & Hitch 1974 The CENTRAL EXECUTIVE controls working memory by focusing attention on one or more of sub-systems and determines flow into LTM. Limited capacity Can process information from any sense (visual, auditory, smell, taste etc) It works like a control mechanism and has responsibility for: Central Executive Switch attention Divide attention Link to LTM Like a conductor instructing an orchestra It is supported by two slave systems, which can be used as storage systems to free up some of its own capacity to deal with more demanding tasks. The slave systems have separate responsibilities and work independently of one another. http://www.youtube.com/watch?v=aseitqCZKQo Dual Task Results Involvement of central executive Average time taken to solve verbal rehearsal Control group None 2.79 ‘the, the, the’ Very little 3.13 ‘1, 2, 3’ Some 3.22 Random six-digit number The most 4.27 Articulatory Phonological Loop The ARTICULATORY PROCESS encodes acoustically and uses REHEARSAL to process information. and the PHONOLOGICAL STORE which also has a limited capacity. Limited capacity The ‘inner voice’ Temporary storage system which stores material in a verbal form and allows you to rehearse verbally ‘articulatory loop’ Words get maintained by repeating it in your head The loop allows for the rehearsal to happen. Offers the explanation of how capacity of STM is 7+/2 items (Miller 1956) and the duration of STM is approx. 18 seconds unless rehearsal takes place (Peterson & Peterson, 1959) The visuo-spatial sketchpad The VISUO-SPATIAL SKETCHPAD encodes and stores visually, limited in capacity and duration. Limited capacity The ‘inner eye’ Temporary memory system for holding visual and/or spatial information (e.g. people’s faces). Evidence for the WMM Word Length Effect – Baddelely (1975) Try it! The phonological loop holds the amount of info that you can say in 2 seconds This makes it hard remember a list of long words e.g. association The phonological loop can rehearse the shorter words quicker therefore, more of list one can be stored and recalled and than list two List 1 List 2 Coin, door, man, six, tap Encyclopaedia, monotonous, disastrous, euphonium, subsequently Evidence for the WMM Dual Task technique experiment (1976) (that we did earlier… ‘the, the, the’) Explains why it’s easier to do two different tasks at the same time than two similar ones watching TV and listening to someone is easier than Uses different slave systems: Phonological loop & Visuo-spatial sketchpad talking to someone while listening to information (e.g. through an ear piece) Uses same slave systems: Phonological loop & Phonological loop The Introduction of the Episodic Buffer http://www.youtube.com/watch?v=3a_cF46UiEU In 2000 Baddeley added the episodic buffer The episodic buffer acts as a 'backup' store which communicates with both long term memory and the This can be thought of components of working memory. as a computer trying to download something …streaming data Evaluating Working Memory Find 2 strengths & 2 limitations Model + The working memory applies to real life tasks: - reading (phonological loop) - problem solving (central executive) - navigation (visual and spatial processing) + Evidence from Baddeley & Hitch (1976) shows that we can process more than one task using STM. + Evidence for phonological loop: word length effect + Helps to explain multi-tasking & learning difficulties - Does not explain how central executive works - The capacity of the central executive has never been measured - WMM is primarily a model of STM so not a comprehensive model Next week Biological Approach to Memory