Memory: Duration, Capacity And Coding Flashcards
What is memory
The process by which we retain information about events that have happened in the past
What is short term memory ?
Memory for events in the present of immediate past
What is long term memory
Memory for events that have happened in the more distant past
Define duration ?
The length of time information can be held in memory
What is the duration of the stm ?
The short term memory store has limited duration
Memories will disappear unless they are rehearsed
What will rehearsal eventually lead to ?
Short term memories will become long term
What method did Peterson and Peterson (1959) use for their stm study ?
24 university students
Experimenter said consonant syllable followed by 3 digit number
Participants had to count back from number in 3s or 4s until told to stop
- this was to stop participant rehearsing syllable -> rehearsal would aid recall
Participants asked to recall the nonsense syllable
Two practice trails then 8 trials
Each trial retention interval was different: 3,6,9,12,15 or 18 seconds
What where the results and conclusion of Petersons and Peterson’s (1959) study
3 second interval - 80% of the syllables were recalled correctly and 2% when there was 18second interval
When rehearsal is prevented, STM duration lasts about 20 seconds
What is the duration of the LTM ?
Last from 2 minutes to 100 years
Unlimited duration
What was the method of bahrick et al 1975 study ?
392 participants
American state of ohio - aged 17-74
High school yearbooks obtained from participants or directly from schools
Recall was tested in various ways
1)photo recognition of 50 photos some from yearbooks
2)free recall where participants recalled all the names of their graduating class
What were the rings and conclusion of bahrick et als research
Participants who were tested within 15 years were about 90% accurate
After 48 years recall reclined to about 70% for photo recognition
Free recall was less good than recognition
After 15 years- 60% accurate
After 48 years - 40% accurate
LTM can last a very long time
What is a limitation of Peterson’s and Peterson’s study (artificial)
A limitation of p+p study is that the stimulus material was artificial.
Memorising consonant syllables does not reflect real life memory activities
Where
What we remember is meaningful
This shows that results cant be generalised to real life experiences and that the study lacks external validity
What is a strength of bahrick et ls research
It has higher external validity Used real life meaningful memories For example Studies into LTM with meaningless pictures had lower recall rates Shepard 1967 Can be generalised to real life
Increases risk confounding variables as participants may still see their classmates today or may have looked at their yearbook over the years and rehearsed
What is capacity
The amount of information that can be held in memory store
What is the capacity for stm and LTM
Mean span for digits - 9.3 items
Mean span for letters - 7.3
