Coding, capacity and duration of memory (key studies) Flashcards
Define capacity
The amount of information that can be held in a memory store
Define coding
The format in which information is stored.
Define duration
The length of time information can be held in memory.
Research on Coding
Describe the study of Alan Baddeley
-participants were given different lists of words
-split into four groups
-group 1 (acoustically similar)
-group 2 (acoustically dissimilar)
-group 3 (semantically similar)
-group 4 (semantically dissimilar)
-shown original words and asked to recall in correct order
Baddeley (1966) findings and conclusion:
STM recall-tended to do worse with acoustically similar words
LTM-did worse with semantically similar words
What is meant by acoustic and semantic.
Acoustic - sound
Semantic - meaning
Evaluation: Identified a clear difference between the LTM and STM stores (Baddeley strength)
P
It identified a clear difference between the LTM and STM stores
E
Baddeley (1966) found that we tend to mix up words that sound familiar when we are using our STM. We tend to mix up words that have similar meanings when we use our LTMs.
E
STM - acoustic
LTM - SEMANTIC
L
supports that MSM has two separate, independent stores.
Evaluation: Baddeley’s study used artificial stimuli rather than meaningful material. (Baddeley Limitation)
P
Uses artificial stimuli in studies rather than meaningful material
E
We form memories from useful things such as names, faces, places etc.
Study uses word lists
E
No personal meaning - may not tell us about coding in different kinds of memory tasks.
Cannot reflect everyday life
L
Study lacks external validity/study has limited application
Describe Millers study - Span of memory and chunking
AIM - How much info can STM hold at one time
Made observations of everday practises
He noted that things come in 7s.
Miller sugguested that the capacity of the STM is about 7 +/- 2.
We use chunking: - group sets of digits or letters into chunks
Evaluation: May have overestimated STM capacity - (Miller Limitation)
One limitation of Miller’s research is that he may have overestimated STM capacity.
Cowan reviewed other research and concluded that the capcity of STM is only about 4 chunks.
This sugguests that the lower end of Miller’s estimate (5 items) is more appropiate than 7 items.
Describe the study by Jacobs - Digit Span
Jacobs found out how much capacity can be held by the STM by measuring digit span.
For example the researcher reads out digits the participant recalls them out loud in the same order. This is done until the participant fails to read them out in same order. This indicates the individuals digit span.
Mean digit span for digits was 9.3 items
Mean span for letters was 7.3
Evaluation: It has been replicated - (Jacobs Strength
One strength of Jacobs’ study is that it has been replicated.
Early research in psychology lacks adequate control of extraneous variables. For example some participants may have been distracted during testing (confounding variable)
Despite this, Jacobs’ findings have been confirmed by other better controlled studies.
Sugguests Jacobs study is a valid test of digit span in STM.
Describe Bahrick’s study - Duration of LTM
AIM -Duration of LTM
studied 392 participants aged between 17 to 74
High school books were obtained from ppts or schools
Recall was tested by photo recognition and name recall.
PHOTO RECOGNITION RESULTS:
Participants within:
15 years of graduation - 90% accurate
48 years of graduation - 70% accurate
FREE RECALL RESULTS
15 years of graduation - 60% accurate
48 years of graduation - 30% accurate
Duration of LTM is lifetime/forever
Evaluation: High external valdity - (Bahrick’s Strength)
One strength of Bahrick’s study is that it has high external validity.
This is because researcher’s investigated meaningful memories.
When studies on LTM were conducted with meaningless pictures, recall rates were lower.
This sugguets that Bahrick’s findings reflect a more real estimate of the duration of the LTM.
Describe Peterson and Peterson’s study - Duration of STM
Aim - Duration of STM
Students were given a consonant syllable (such as GPS) and 3 digit number to remember.
The students counted backwards to prevent mental rehersal.
On each trial they were stop after varying periods of time.
They found out that STM duration is around 18 seconds.
Evaluation: Uses articifical stimuli in studies - (Peterson and Peterson Limitation)
P
Uses artificial stimuli rather than meaningful material
E
We form memories from useful things such as names, faces, places etc.
Study uses consonant syllables(CS)
E
No personal meaning
Recalling of CS cannot be applicable to everyday life
L
Study lacks external validity
