Cognitive

Capacity

How many items a memory store can hold. STM = 5-9 items

Duration

How long a memory will last

Encoding

Process of formatting information in different ways

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 - measures of central tendency + measures of dispersion

Measures of central tendency

• Mean

• Median

• Mode

Measures of dispersion

• SD

• Range

Jacobs

• Researched capacity

• STM (MSM)

• Digit span

Jacobs Aim

See 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 = 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 data

Advantages of quantitative data

• Objective = reliable + scientific

• Good for comparisons - can be turned into statistics.

• Allows comparisons of large groups + identifying trends.

• Simple + can summarise data quickly.

Disadvantage of quantitative data

• Reductionist - lack of detail

• Lacks validity - cannot explain circumstance

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 – 10% forgotten

• 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 - direction of the findings is predicted

Non-directional Hypothesis

Two tailed - Direction of the findings is unknown, but a difference is predicted.

Null hypothesis

Assumption that there is no relationship, difference or association between the two variables

Independent groups design

- Different people in each condition of IV
- No one in more than 1 condition
- Each participant experiences IV once

Repeated measures design

- All participants do experimental + control condition
- Experience every condition of IV

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 - participants' performance goes down through boredom or exhaustion

Practice effects

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).

- Some might do experimental condition first, then 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)

• 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

- removes participant variables

- can be more sure it is the interval delay affecting the trigrams correctly recalled not individual differences like shorter processing speed.

Peterson and Peterson experimental design - disadvantages

- Repeated measures design
- Order effects + 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.

- Decreased validity

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 capacity of visual information (normal) than auditory letters + digits (2)

• 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 maths 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 looks like, light, colour, shapes + movement).

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

• It can temporarily hold and manipulate visual + 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 WM + 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, EB allows this two-way communication between WM and LTM.

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.

• Participants given 2 different tasks.

• Task 1: Inner voice + inner ear - had to memorise a series of letters.

• Task 2: Only inner voice - had to decide if letters rhymed.

Phonological Loop - location

- Left hemisphere (temporal lobe.)

VSSP - location

- Right hemisphere
- Simple tasks = occipital lobe

- Complicated tasks = parietal lobe

Episodic Buffer - location

- Both hemispheres (bilateral), particularly in the hippocampus (links to 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 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

• Little information

• Its role in terms of attention + decision making in WM is vage + untestable.

• Psychologists argue it could be subdivided, suggesting WMM is incomplete.

WMM - Real life application - Dyslexia

• People with dyslexia have problems with WM + have phonological deficits.

• Poor WM make it difficult to concentrate on tasks with multiple steps.

• Holding several pieces of phonological informations makes blending words difficult.

• May read more slowly because of difficulty associating sounds with words.

WMM - Real life application - Dyslexia - How teachers can support

• Split instructions into steps

• Giving students time to process

• Present written information concisely

Sampling

• Pyschologists identify a target population and recruit a representative sample.

Generalisation

• If sample is accurate, you can generalise results + conclusions to others in target population.

Stratified sampling

- Researcher divides target population into sub-groups (strata) - represent the population demographic spread

- Researcher randomly selects a representative number of participants from each strata to take part in study

Stratified sampling - strengths

• Representative - participants matched on same characteristics of target population - increased validity.

• Stratified detail - unbiased - researcher doesn’t influence sample - characteristics mirror target population.

Stratified sampling - weaknesses

• Complicated - requires accurate knowledge of characteristics of target population.

• Time consuming - must identify relevant categories, work out percentages + randomly select appropriate participants.

Opportunity sampling

Participants chosen based on proximity to researcher, those who happen to be available at the time.

Volunteer sampling

Study advertised and participants volunteer to take part.

Random sampling

Identify everyone in target population and select the number of participants needed in a way that gives whole population an equal chance of being picked (e.g: name pulled out of a hat).

Random sampling - strengths

• Unbiased - all members of target population have equal chance of selection, removes bias in choosing participants in conditions.

• Easy to conduct, requires little knowledge of participants.

Random sampling - weaknesses

• Difficult procedure to obtain a truly representative sample of target population, requires time to produce something that would be reliable + valid.

• Any 2 random samples drawn may have different individual characteristics, may become a confounding variable.

Opportunity sampling - strengths

• Practical + efficient, simple method reduces cost.

• Convenient to conduct - participants are readily available so doesn’t take excessive time or effort.

Opportunity sampling - weaknesses

• Highly unlikely it will yield a representative sample of target population as sample is taken from small part of it, difficult to generalise findings.

• Easy to bias research out of convenience, e.g: choosing participants from your own immediate environment of cultural group - subjective expectations can influence who is approached.

Volunteer sampling - strengths

• Simple + practical, requires less work that random sampling, participants offur time to you so requires minimal effort other than creating advertisment.

• Ethical, participants self refer themselves, ethical and appropriate once informed consent is achieved.

Volunteer sampling - weaknesses

• Unrepresentative of target population, self selected samples tend to have atypical characteristics, creates volunteer bias.

• Loss of control + randomness, some people will choose not to take part.

Reconstruction

The idea that we alter information we have stored when we recall it, based on prior expectations or knowledge

Confabulation

Schemas fill in gaps in memory and put pressure on our mind to remember things in a way that fits in with the schema, removing or changing details. 

Schema theory

• How humans process incoming information, relate it to existing knowledge, + use it.

• Based on the assumption that humans are active processors of information.

• If information is missing, the brain fills in the blanks based on existing schemas.

• This can result in mistakes. 

Accommodation - Schemas

Changing our memories to keep our schemas in tact.

Levelling - Schemas

Removing details from memory to fit schemas.

Sharpening - Schemas

Adding or exagerrating details to fit schemas.

Schema

A stored experience or prior knowledge that forms a mental representation of the world - can influence how we categorise + recall information from our memory.