Cognitive

Capacity

Capacity involves how many items a memory store can hold. In the STM, capacity is between 5 to 9 items.

Duration

The duration involves how long a memory will last. For example, the STM can hold information for 0-30 seconds.

Encoding

The process of formatting information in different ways. In STM encoding is said to be acoustic.

Stages of MSM

• Environmental stimuli

• Sensory memory

• STM

• LTM

Sensory store (MSM)

• After senses detect stimuli

• If paid attention to, transferred to STM

STM (MSM)

• Acoustic encoding

• Capacity (5-9) (Jacobs)

• Duration (15-30 seconds)

• If rehearsed, transferred to LTM

LTM (MSM)

• Semantically encoded

• Unlimited capacity

• Lifelong duration

Atkinson & Shiffrin

MSM

Descriptive statistics

• Brief informational coefficients that summarise a given data set, either a representation of the entire population or a sample of a population. 

• Broken down into measures of central tendency and measures of dispersion

Measures of central tendency

• Mean

• Median

• Mode

Measures of dispersion

• SD

• Range

Jacobs

• Researched capacity

• STM (MSM)

• Digit span

Jacobs Aim

• Investigate how much information can be stored in STM.

Digit span procedure

• Presented with sequence of letters or digits.

• Repeat back to experimenter in same order.

• Began with 3 items, increased by 1 each time until participant consistently failed.

• Sequence length recalled correctly on at least half the trials was participant’s Digit span.

Jacobs conclusions

• STM has limited capacity (5-9)

• Capaciy not determined by nature of information but size of digit span.

• Digit span increased with age

Jacobs validity & generalisability - negative

• Lacks mundane realism - not representative of everyday memory demands.

• Artificial tasks may have biased results.

• Letters/digits not meaninful information so may be remembered less well.

• STM Capacity may be greater for everyday memory.

• Cannot be genaralised to real life memory.

Quantitative data

Numerical data

Qualitative data

Descriptive written data e.g: open questions

Advantages of quantitative data

• Objective, makes it reliable and scientific.

• Good for comparisons as it can be turned into statistics.

• Allows comparisons of large groups and identifying trends.

• Simple and can summarise data quickly.

Disadvantage of quantitative data

• Reductionist - lack of detail

• Lacks validity

Advantages of qualitative data

• Holisitc, conveys meaning and individuality

• Highly valid

Disadvantage of qualitative data

• Subjective

• Unreliable

• Hard to make comparisons

• Hard to analyse large groups

• Lengthy & time consuming

Primary data

Gathered first hand by the researcher

Secondary data

Information already published

Brown-Peterson technique

• Involves blocking rehearsal by getting participants to do an interference task like counting backwards in threes

Peterson and Peterson - Brown-Peterson technique results

• 3s – 90% remembered

• 9s – 70% was forgotten

• 18s – 90% forgotten

Suggests decay occurs in STM over a period of 18-30 seconds if rehearsal is prevented supporting the rehearsal process of transfer to LTM.

Peterson and Peterson - IV

Interference task number of seconds eg. 3,6,9,12,15

Peterson and Peterson - DV

Number of trigrams correctly recalled after every trial

Hypothesis

A predictable statement of what you expect to find after completing your research.

Directional Hypothesis

One tailed - means the direction of the findings is predicted. eg. first division footballers will score more penalties than second division footballers.

Non-directional Hypothesis

Two tailed - means the direction of the findings is not known, however a difference is predicted. eg. There will be a difference between the number of penalties scored between first and second division footballers. 

Null hypothesis

An assumption that there is no relationship or difference or association in the population from which a sample is taken with respect to the variables being studied. eg. There will be no difference between the number of penalties scored between first and second division footballers.

Independent groups design

Completely different groups of people in each condition of the IV, no one gets to be in more than one condition. Each participant only experiences the IV once.

Repeated measures design

Everyone gets to be in the experimental condition and the control condition. They experience every condition of the IV. Can suffer from order effects. If you test the same group of people twice, then they might behave differently the second time because they’re familiar with the test – or bored with it.

Independent groups design - strengths

• No order effects

• Less demand characteristics

Independent groups design - weaknesses

• Participant variables

• Needs more participants

Repeated measures design - weaknesses

• Order effects

• More demand characteristics

Repeated measures design - strengths

• No participant variables

• Needs fewer participants

Fatigue effects

Order effects where the participants' performance goes down through boredom or exhaustion

Practice effects

Are order effects where the participants' performance goes up through familiarity with the test

Demand characteristics

Participants behave unnaturally because they are trying to do what they think the researchers want them to do.

Solutions to the problem of order effects

• Randomisation

• Counter-balancing

Randomisation

Determining which condition a participant experiences by random chance (tossing a coin, drawing a card). Some might do the experimental condition first, then the control condition.

Counter-balancing

Split the group into sub-groups - one sub-group does the experimental condition first, then the control, the other sub-group does it the other way round.

Matched pairs design - weaknesses

• Not always possible to find a participant who is a good match, especially if the experiment looks at rare cases (eg Schmolck's study of brain damaged patients)

• Not always possible to operationalise them (eg Schmolck doesn't seem to have matched "educational level" very successfully, because it still made a difference to the results, causing some of the MTL patients to outperform the control group)

Peterson and Peterson experimental design - advantages

Repeated measures design - Using same participants eliminates any participant variables that could impact the results. So they can be more certain that it is the interval delay affecting the trigram correctly recalled and not individual differences such as shorter processing speed.

Peterson and Peterson experimental design - disadvantages

Repeated measures design - order effects and possible demand characteristics. After repeating the conditions, the participant might start to guess what the researcher is trying to measure and could therefore change their responses. May impact the validity of the study.

Primacy/recency effect

When participants are given a list of words and asked to recall them, the first and last words on the list were recalled better than the words in the middle.

Primary effect

Participants have rehearsed these words more and transferred them into the long term memory.

Secondary effect

These words are still in the short term memory.

HM

• Case study

• Brain injury due to surgery to relieve his seizures as a consequence of epilepsy.

• Had part of temporal lobe (hippocampus) removed.

• Had severe memory loss.

HM - Supports WMM

• New information entering STM was not entering LTM.

• Suggests there are 2 separate stores that process information.

• Remembered events before surgery but not after.

• Memory stores must be located in different regions of brain.

KF

• Brain damage in motorcycle incident at 17.

• STM was reduced (2 items)

KF - supports WMM

• Despite shortened STM, LTM remained fine.

• Information could go straight to LTM.

• Greater short term forgetting of auditory letters + digits than visual.

• Suggests MSM is simplifying STM, there are multiple stores.

Why was the WMM developed?

• MSM is too simplistic, assumes STM and LTM act as one store

Baddeley & Hitch - belief about STM

• STM is more useful in everyday life than previously assumed. E.g. working on a mathematical problem, STM can keep track of where we get to in a problem.

• Rehearsal is not the only process that occurs in STM

Working memory model proposal about STM

Active processor made up of several stores; each section having a limited capacity.

4 separate components to WMM

• Central Executive

• Phonological loop

• Visuo spatial sketchpad

• Episodic buffer. 

Phonological loop

• Slave system controlled by the Central executive.

• Deals with sound based information and is made up of two separate components.

• It has a limited capacity.  

Articulatory process

• Responsible for rehearsing verbal sounds (the inner voice)

• Duration believed to be 2 secs.

Phonological store

• Responsible for receiving + storing sounds.

• Focuses on speech perception(the inner ear)

• Stores the words you hear in the order that they were presented.

Visuo-spatial sketchpad

• Inner eye

• Responsible for visual information. (What we see + what an object might look like, light, colour, shapes + tracking movement. You see the object in your mind's eye).

• Spatial information relates to the location of those objects in a space and helps us to know where things are in relation to one another.

• It can temporarily hold and manipulate visual and spatial information

Central executive

• Controls the slave systems.

• In charge of what we pay attention to.

• Has a limited capacity

Episodic buffer

• A back up store integrating all the components of working memory + LTM.

• Not limited or focused on one type of encoding

• Can store + process visual + verbal STMs.

• If WM needs to combine current information + previous LTM then the EB is the store that allows for this two-way communication between WM and LTM to take place.

Paulesu et al

• Research to suggest there are separate components to Phonological loop.

Paulesu et al - Findings

• Found different parts of the phonological loop activated different brain areas.

• Inner voice showed activity in broca’s area + the supramarginal gyrus was active during task 1 suggesting it may be linked to inner ear.

• Therefore this research suggests that the WMM has separate components in the phonological loop.

Paulesu et al - Procedure

• Volunteers placed in a PET scan to measure blood flow in brain whilst performing memory tasks.

• Pts given 2 different tasks.

• Task 1: using inner voice + inner ear, pts had to memorise a series of letters.

• Task 2: Using only inner voice, pts had to make judgement as to whether letters rhymed.

Phonological Loop - location

Seems to be located in the left hemisphere, specifically the temporal lobe.

VSSP - location

In the right hemisphere, with simple tasks in the occipital lobe + complicated ones in the parietal lobe.

Episodic Buffer - location

Seems to be in both hemispheres (bilateral) but particularly in the hippocampus (which links to the Schmolck et al study)

Central Executive - location

Seems to be linked to the frontal lobes

Studies of dual task performance support the separate slave systems

• Involves doing 2 tasks at the same time.

• Allows us to learn if certain mental functions work separately or share the same resources.

• If each component has limited capacity + each component is relatively independent of the other components we would expect that if 2 tasks use the same component, they can’t be performed successfully together. 

• But if two tasks used different components, it should be possible to perform them as well together as separately.

• Reading and counting out loud at the same time are difficult as they both require the limited resources of the phonological loop.

Working Memory - dual tasks

• Studies show that performing two visual tasks or two verbal tasks simultaneously leads to poorer performance compared to doing them separately.

• Suggests limited capacity within the same component of working memory.

• Performing one visual task + one verbal task together doesn’t impair performance.

• Supports WMM showing separate components (Visuospatial Sketchpad & Phonological Loop)

WMM research - weaknesses - validity

• Many of dual task studies carried out in controlled environments.

• Many involve artificial memory tests.

• Low ecological validity + mundane realism.

WMM research - weaknesses - SDB

Pts know they are taking part in psychological research and may adjust answers.

WMM research - weaknesses - visuospatial sketchpad

• Wolbers et al research on people blind from birth.

• Compared spatial awareness in sighted volunteers + people blind from birth.

• Brain scans showed they could use other senses can be used to understand spatial awareness.

• Spatial awareness not dependent on vision, suggests Baddeley + Hitch’s idea of VSS is too simplistic.

WMM research - weaknesses - central executive