Memory

types of memory

short term memory: temporary memory store for events in present or immediate past

Long term memory: more permanent memory store for events that happened in distant past

coding

Format in which information is stored in the various memory stores

types of coding

visual: image

Acoustic: sound

Semantic: meaning

coding research conditions

• Alan Baddeley gave different words to 4 groups of participants

1. (Acoustically similar): words sound similar

2. (Acoustically dissimilar): words sound different

3. (Semantically similar): words with similar meaning

4. (Semantically dissimilar): words with different meaning

Coding research procedure

• participants shown original words and asked to remember then in order

STM: did worse with acoustically similar

LTM: did worse with semantically similar

Coding research conclusion

STM: acoustic confusion, so STM coded acoustically

LTM: semantic confusion, so LTM coded semantically

Capacity STM research

Joseph Jacobs

• read out 4 digits and participants recall them in order

• If participant got it correct, the number of digit went up

• Gives us indication of digit span

• Mean digits ranged between 9±2

• Mean letter ranged between 7±2

Capacity of LTM

Linton

• conducted an autobiographical study to record 6 years of events from her past

• Randomly selected pairs of records once a month and try to chronologically order date of each recorded event

• Recorded 5,500 events

• She could recall 70% accurately

• Memory decreased 5% a year

Duration STM research

Lloyd and Margaret Peterson

• participants had to try remember and recall three-letter strings

• Tested after 3 seconds could remember 80%

• Tested after 18 seconds could remember 10%

Conc: STM lasts 15-30 seconds, average 18s

Strengths of STM capacity research

1. Lab experiment: high internal validity

2. Easily replicable

Limitations of STM capacity research

1. Low mundane realism

2. Extraneous variables

3. Order effects

4. Lacks ecological validity

Duration of LTM research

Bahrick

• Photo recognition

  • 15 years: 90%

  • 48 years: 70%

• Free recall of names

  • 15 years: 60%

  • 48 years: 30%

• Name recognition

  • 15 years: 90%

  • 48 years: 80%

Strengths of LTM duration research

1. Lab experiment

2. High mundane realism

Limitations of LTM duration research

1. Extraneous variables

MMM

Atkinson and Shiffrin

MMM is a theatrical model that explains how information flows from one storage system to another

Sensory register (SR)

information is initially stored in the sensory register that is not unitary, it decides which information is passed onto STM

Duration: less than half a second

Capacity: very high

SR memory stores

ionic memory - visual information

Echoic memory - sound

MSM flow chart

Sensory register → (attention) STM → (maintenance rehearsal) LTM

information loss

SR - decay

STM - decay and displacement

LTM - decay and interference

Case study 1

Clive Wearing

• viral infection suffered brain damage to hippocampus

• STM was intact, unable to transfer memories from STM to LTM

• Suggests STM and LTM are unitary stores

Case study 2

Scoville and Milner

• had brain damage caused by operation to remove hippocampus

• Could not form new LTM, but STM was intactc

• Suggests STM and LTM are unitary stores

Strengths of case studies

• gives rich detailed information about the case

• Investigate rare behaviour

Limitations of case studies

• Each case is unique so not generalisable

• May have to recall past events so memory distortion

• Research bias

Case study 1 against MMM

Shallice and Warrington

• was in a motorcycle accident, brain damage

• No problem with LTM, but some of STM was impaired

• Difficulty with verbal info in STM, but normal visual info in STM

• Shows it is not a unitary store

Elaborative rehearsal

• limitation of MMM

• deeper, semantic level of processing, connecting new information to existing knowledge

• Leads to more usable long-term memory

• Whereas maintenance rehearsal leads to weaker memories

WMM

• proposed by Baddeley and Hitch

• Replaces MSM, shifting focus from STM to working memory

• STM is an active store, holding information

Parts of WMM

• central executive

• Phonological loop

• Visuo-spatial sketchpad

• Episodic buffer

Central executive

• monitors incoming information

• Manages attention

• Allocates tasks to ‘slave systems’

• Limited capacity, only holds onto one piece of information at a time

Phonological loop

temporary stores language based information

parts of phonological loop

Articulatory rehearsal process: help repeat words or sounds in ones head. Converts written words into sounds

Phonological store: holds auditory speech information and the order it was heard

visuo-spatial sketchpad

temporary store of visual and spatial information

parts of visuo-spatial sketchpad

visual cache: stores visual data about form and colour (WHAT)

Inner scribe: records arrangement of objects in the visual field (WHERE)

episodic buffer

• temporary store that integrates visual, spatial, and verbal information by other stores

• Limited capacity

• Links cognitive processes like perception