Session 6: Models of Memory

Evaluate two models or theories of one cognitive process with reference to relevant research studies What the command term means… Evaluate: Make an appraisal by weighing up the strengths and limitations. What the command term means… Evaluate: Make an appraisal by weighing up the strengths and limitations.

 We will be evaluating TWO MODELS OF MEMORY these have been developed by cognitive psychologists to explain how memory works The two models of memory you will learn are: 1. Multi-store Model (Atkinson & Shiffrin, 1968) 2. Working Memory Model (Baddeley and Hitch, 1974 )

 Definition: The mental processes involved in storing and retrieving information Essential Questions:  How does our mind organise data?  How do psychologists study memory?

 One of the first models to give an overview of basic structure of memory  Inspired by computer science  Although model seems simplistic today it did spark off the idea of humans as information processors  Has been one of most influential models attempting to describe memory system

Based on assumption that memory consists of a number of separate stores and that memory is sequential

 Memory stores are structural components that include control processes (e.g. attention, coding and rehearsal).  Rehearsal ensures the transfer of information from short term memory to long term memory

Sensory Memory Registers sensory information and stores it for around 1-4 seconds Information in sensory information is modality specific (i.e. Related to different senses) Only a small amount of sensory memory will be transferred to STM store This depends on whether or not it is attended to

Short Term Memory (STM) Has limited capacity (around 7 items) Limited duration (around 6-12 seconds) Information in STM is transferred to LTM if rehearsed, if not it is lost

Long Term Memory (LTM) Believed to be of indefinite duration Potentially unlimited capacity

An investigation into short term memory

 I am about to carry out an experiment into the serial position effect in memory.  You will be shown a series of words and asked to remember them. Then, you will be asked to recall as many of the words as you can. The experiment should not take longer than five minutes.  You do not have to take part if you don’t want to. If you take part but do not want your recall made public, I will respect your wishes. The results are completely anonymous.  Is there anybody who does not wish to take part?

 You will need some paper and pen to write down the words you remember.  When we start, you will see a series of slides with one word on each slide  After the last slide, you will be asked to recall as many of the words I have presented in any order.  Any questions?

Mask

Wine

Coat

Book

Music

Stamp

Hinge

Horse

Goldfish

King

Printer

Clock

Knife

Carpet

Kite

Phone

Pepper

Arrow

Jelly

Van

Newspaper

Square

Cup

Flower

Shoe

Bed

Kitten

Diamond

Gun

Tree

 Now write down as many of the words that you can remember, in any order  You will have 2 minutes for this

 Thank you for taking part in the experiment.  The theory is that words at the beginning and end of the list are more likely to be recalled than words from the middle of the list.

Let’s tally up which ones you remembered

The Serial Position Effect Believed to be linked to rehearsal i.e. People rehearse things to remember them Serial position effect suggests people remember things better if they are either the first (primacy effects) or the last (recency effect) item in a list to remember

The Serial Position Effect: Glanzer and Cunitz (1966) Aim Aim: to investigate serial position effect in free recall Procedure Procedure: laboratory experiment where participants heard a list of items and then immediately had to recall them in any order Results: Results: Participants recalled words from beginning and end of list the best. Results showed a U-shaped curve If participants were given a filler task just after hearing words the primacy effect disappeared and the recency effect remained

The Serial Position Effect: Glanzer and Cunitz (1966) The recency effect could be due to words still being active in STM Rehearsal could be a factor in transfer of information into LTMEvaluation: Study supports idea of multiple stores (STM and LTM). Controlled lab experiment with highly controlled variables but there is no random allocation of participants to conditions so it is not a true experiment May be issues with ecological validity

Case studies of individuals with amnesia due to brain damage Amnesia is caused by damage to the hippocampus and related networks involved in storage of new memories MRI scans show that HM had severe damage to hippocampus which is critical of storage into LTM HM could store new procedural memories but was unable to store any explicit new memories. This is evidence that memory contains different systems

Strengths  Model pioneered the new approach to memory where humans are seen as information processors  Model’s conceptualisation of memory as multi- stored is supported by research  The overall model has been modified, for example, Baddeley and Hitch (1974) with their new version of short term memory, the ‘working memory’ model

Limitations  Model is very simplistic and cannot account for how interaction between the different stores takes place  Research into encoding of LTM has challenged the single-store version of LTM. It is now accepted that LTM contains several stores (e.g. semantic, episodic, procedural)

 Atkinson’s and Shiffrin’s (1968)multi-store model was extremely successful in terms of the amount of research it generated.  However, as a result of this research, it became apparent that there were a number of problems with their ideas concerning the characteristics of short-term memory.

 Studied the MSM model and believed that the model’s short term memory (STM) store lacked detail  Suggested the working memory model as an alternative to STM  It is a far more complex explanation of STM  Model changed view that STM is unitary i.e. Suggested STM made up of different components  LTM as a more passive store that holds previously learned material for use by the STM when needed.

So what’s the difference between STM and working memory?? active  Seen as an active store used to hold and manipulate information  Originally made up of three separate parts  Model been developed over years to include findings from research- a 4th component, the episodic buffer, was added in 2000

Working memory includes 4 separate components each with specialised function Supervisory System: 1. The Central Executive Slave Systems: 2. The phonological loop 3. The visuo-spatial sketchpad 4. The episodic buffer (2000)

The Working Memory Model (Baddeley & Hitch, 1974)

 Monitors and coordinates other components  Modality free so can process information in any modality  According to model, most important part of the working memory because it was in complete control of other components  Has ability to store information but its capacity is limited.  Allocates data to the subsystems  Also deals with cognitive tasks such as mental arithmetic and problem solving.  Decides what working memory pays attention to. E.G. two activities sometimes come into conflict such as driving a car and talking. Rather than hitting a cyclist who is wobbling all over the road, it is preferable to stop talking and concentrate on driving. The central executive directs attention and gives priority to particular activities.

 Baddeley uses metaphor of a company boss to describe central executive  Company boss makes decisions about which issues deserve attention and which should be ignored.  They also select strategies for dealing with problems, but like any person in the company, the boss can only do a limited number of things at the same time. The boss of a company will collect information from a number of different sources.  If we continue applying this metaphor, then we can see the central executive in working memory integrating (i.e. combining) information from two assistants (the phonological loop and the visuo-spatial sketchpad) and also drawing on information held in a large database (long-term memory). However, despite its importance in the working-memory model, we know considerably less about this component than the subsystems it controls.

 Read the digits below to yourself and then, immediately, close your eyes and try to remember the digits, silently. After a few seconds, repeat them aloud

How did you accomplish the task?  Many people report that when they read the digits silently they “hear” them in their head, in the sound of their own voice.  Then, when their eyes are closed, they “rehearse” the sounds, repeating the words silently to themselves.  The subjective experience seems to be of speaking the digits “in your mind.” Does this experience match yours? The idea that verbal working memory involves both a “mind’s ear” (that heard the digits when you read them) and a “mind’s voice” (that repeated them in rehearsal) is central to current thinking about the phonological loop.

 Deals with spoken and written material  Divided into 2 further components: 1.Phonological Store (“inner ear)” – Linked to speech perception Holds information in speech- based form (i.e. spoken words) for 1-2 seconds. Spoken words enter the store directly. Written words must first be converted into an articulatory (spoken) code before they can enter the phonological store. 2.Articulatory control process (“inner voice”) – linked to speech production) acts like an inner voice rehearsing information from the phonological store. It circulates information round and round like a tape loop. This is how we remember a telephone number we have just heard. As long as we keep repeating it, we can retain the information in working memory ◦ Phonological store ( holds words heard) ◦ Articulatory process ( linked to speech production, rehearses info from phonological store aloud in our heads)

 How many windows are there in the front of your house?  Where is the door?  Can you draw it?

 You probably find yourself picturing the front of your house and counting the windows. An image has been retrieved from LTM and pictured on the visuo-spatial sketchpad.

 The “inner eye”  Visual = what things look like  Spatial = relationships between things  Handles visual and spatial information from either sensory memory (visual information) or from LTM (images)  The eyes are used to store and manipulate visual and spatial information such as remembering colours or shapes.  Plays an important role in helping us keep track of where we are in relation to other objects as we move through our environment  The sketchpad also displays and manipulates visual and spatial information held in long-term memory.

 26 years after the original working memory model, Baddeley added this third slave system as he realised model needed a more general store.  Limited capacity temporary storage system  Assumed to be controlled by the central executive through conscious awareness  Handles information in various modalities  Resembles the concept of episodic memory Links together every piece of information from all other elements of working memory with further information relating to time and order. This process enables memories to be prepared for episodic LTM storage.

 There is evidence of working memory in dual tasks experiments  WM Model assumes there is a division of tasks between the different systems according to modality  The working memory model makes the following two predictions for dual task experiments: ◦ 1. If two tasks make use of the same component (of working memory), they cannot be performed successfully together. ◦ 2. If two tasks make use of different components, it should be possible to perform them as well as together as separately.  Results from Dual task experiments support the view that the phonological loop and the sketchpad are separate systems within working memory.

Baddeley and Hitch (1976)  Aim: To investigate if participants can use different parts of working memory at the same time.  Method: Conducted an experiment in which participants were asked to perform two tasks at the same time (dual task technique) - a digit span task which required them to repeat a list of numbers, and a verbal reasoning task which required them to answer true or false to various questions (e.g. B is followed by A?).  Results: As the number of digits increased in the digit span tasks, participants took longer to answer the reasoning questions, but not much longer - only fractions of a second. And, they didn't make any more errors in the verbal reasoning tasks as the number of digits increased.  Conclusion: The verbal reasoning task made use of the central executive and the digit span task made use of the phonological loop.

Quinn and McConnel (1996)  Asked participants to learn a list of words by using either imagery or rehearsal  Task performed on its own or in the presence of a concurrent visual noise (changing patterns of dots) or concurrent verbal noise (speech in a foreign language)  Results showed learning words by imagery was not affected by a concurrent verbal task but was disturbed by a concurrent visual task  The opposite was found in the rehearsal condition  Indicates imagery processing uses visuo-spatial sketchpad whereas verbal processing uses the phonological loop  If 2 tasks used the same component, performance deteriorated  Study lends support to different modality specific systems and the idea of limited processing capacity

Remember the following words:

Harm

Twice

Calm

Share

Tree

Book

Sun

Four

Key

Short

How many did you get right?  Harm  Twice  Calm  Share  Tree  Book  Sun  Four  Key  Short

Association

Representative

Discouragement

Meaningfulness

Suppression

Enhancing

Component

Performances

Forgetting

Damaging

 How many did you get right this time?  Association  Representative  Discouragement  Meaningfulness  Suppression  Enhancing  Component  Performances  Forgetting  Damaging

The phonological loop can offer an explanation of why the word- length effect occurs – the fact that people cope better with short words than long words in working memory (STM).

 It seems that the phonological loop holds the amount of information that you can say in seconds (Baddeley et al, 1975).  This makes it hard to remember a list of long words such as ‘association’ and ‘representative’ compared to shorter words like ‘harm’ and ‘twice’ and therefore inhibits rehearsal of longer words!

 Repeat the word ‘the’ whilst looking at the list

 Word length effect disappears if a person is given an articulatory suppression task (‘the, the, the’ while reading the words).  The repetitive task ties up the articulatory process and means you can’t rehearse the shorter words more quickly than the longer ones, so the word length effect disappears.  This provided evidence for WMM

 The KF Case Study supports the Working Memory Model.  KF suffered brain damage from a motorcycle accident that damaged his short-term memory.  KF's impairment was mainly for verbal information - his memory for visual information was largely unaffected.  This shows that there are separate STM components for visual information and verbal information

Strengths  Researchers today generally agree that short-term memory is made up of a number of components or subsystems. The working memory model has replaced the idea of a unitary (one part) STM as suggested by the MSM model.  The working memory model explains a lot more than the MSM model. It makes sense of a range of tasks - verbal reasoning, comprehension, reading, problem solving and visual and spatial processing  The KF Case Study supports the Working Memory Model. KF suffered brain damage from a motorcycle accident that damaged his short-term memory. KF's impairment was mainly for verbal information - his memory for visual information was largely unaffected. This shows that there are separate STM components for visual information and verbal information  Working memory is supported by dual task study research and by word-length effect  Brain scans show different areas of the brain are used for visual and verbal tasks which supports the WMM.

Limitations  Central Executive which is still not clearly explained nor understood. Its functions are unclear and extremely difficult to test. Suggested that it is possible to divide the Central Executive into smaller systems but has thus far failed to positively do so.  Episodic Buffer which was brought into the equation remains a mystery in terms of how it binds together information from the model’s other parts and LTM.  Lieberman criticizes the working memory model as the visuo-spatial sketchpad implies that all spatial information was first visual (they are linked). However, Lieberman points out that blind people have excellent spatial awareness although they have never had any visual information. Lieberman argues that the VSS should be separated into two different components: one for visual information and one for spatial.  Working memory only involves STM so it is not a comprehensive model of memory (as it does not include SM or LTM).  Fails to account for musical memory as we are able to listen to instrumental music without impairing performance on other acoustic tasks.

 Draw your own flow chart for both models of memory  Include some facts for each structural component of memory  Use page 73 of your textbook to help you