Coding, capacity, duration

AQA A - Level psychology memory

What is coding?

Porcess of converting information between different forms

Describe Alan Baddeley’s research into coding - Procedure

. Four Groups =

• G1 - Acoustically similar words (sound similar)

• G2 - Acoustically dissimilar words (don’t sound similar)

• G3 - Semantically similar words (mean similar things)

• G4 - Semantically dissimilar words (don’t have similar meanings)

. Pps shown original words to recall in a correct order.

Describe the findings of Baddeley’s research into coding

. Pps struggled to recall acoustically similar words from short term memory.

. They struggled more with semantically similar words when recalling from long term memory

What do the findings of Baddeley’s research into coding suggest?

Info is coded acoustically in STM and semantically in LTM

What is capacity?

The amount of information that can be held in a memory store

Describe Jacobs’s digit span research on capacity - procedure

. Researcher reads out four digits

. Pps recalls these out loud in correct order

. If order is correct, research reads out five and so on

. Continues until pps can no longer recall list correctly

Describe the findings of Jacobs’s digit span research

. Mean span for digits = 9.3

. Mean span for letters = 7.3

What did George Miller say about span of memory?

. Made observations about everyday practice

. Noted that things come in 7s e.g 7 days of week, 7 notes in music

. He thought the span of STM is 7±2 items

What did Miller say about the span of memory?

We can recall 5 letters as easily as we can recall 5 numbers - do this by chunking

. chunking is the grouping of sets of digits or units into chunks

Describe the procedure of Peterson & Peterson’s research into the duration of STM

. 24 students given a consonant syllable (e.g HYD) to remember

. Also given a 3-digit number

. Student counts back from number until told to stop

. Counting backwards prevents mental rehearsal of syllable

. Told to stop after 3,6,9,12,15 or 18 seconds

. Then had to recall consonant syllable

Describe the findings of Peterson and Peterson’s research into the duration of LTM.

. After 3 seconds, recall about 80%

. After 18 seconds, recall about 3%

What did Peterson and Peterson conclude about the duration of LTM from their research?

. Duration of STM may be around 18 seconds unless we rehearse info

Describe the procedure of Bahrick’s research into the duration of LTM

. 392 American pps age 17-74

. High school yearbooks obtained for each pps

. Recall of class mates tested by free recall or photo recognition

Describe the findings of Bahrick’s research into the duration of LTM

. Pps testes within 15 years of graduation about 90% accurate in photo recognition. After 48 years, recall declined to about 70%

. Recall less accurate in free recall - 60% after 15 years, 30% after 48 years

What can be concluded about the duration of LTM from Bahrick’s research

. LTM may last up to a lifetime for some material

Separate memory stores as a strength of Baddeley’s research into coding

P - Identifies a clear difference between two memory stores

E - Research has shown some exceptions to his research but the idea that STM uses mostly acoustic coding has stood the test of time

E - Important step in our understanding of the memory system which led to the multi store model

Artificial stimuli as a limitation of Baddeley’s study

P - Uses artificial stimuli rather than meaningful words

E - Word lists had no personal meaning to the pps. Findings may not tell us much about coding in different kinds of memory tasks especially in everyday life. Semantic coding may be used when processing more meaningful info, even in STM

E - Findings from study have limited application

Validity as a strength of Jacobs’ study on capacity

P - Study has been replicated

E - The study is old so may have laced adequate controls, e.g pps being distracted. Despite this the findings have been confirmed by other better controlled studies

E - Jacob’s study is a valid test of digit span in STM

Limitation of Miller’s research - not so many chunks

P - Miller may have overestimates STM capacity

E - Cowan reviews other research and concluded that the capacity of STM is only about 4±1 chunks

E - Suggests that the lower end of Miller’s estimate is more appropriate than seven items

Meaningless stimuli as a limitation of Peterson and Peterson’s study

P - Stimulus material was artificial

E - Recalling consonant syllables does not reflect the often meaningful material we try and remember day to day

E - Study lacked external validity

High external validity as a strength of Bahrick’s research

P - High external validity

E - Researchers investigated meaningful memories e.g. peoples names and faces. When studies on LTM were conducted on meaningless pictures, recall was lower

E - Suggests Bahrick’s findings reflect a more real estimate of the duration of LTM