Memory - Coding, Capacity And Duration Flashcards
Short-term memory
The limited capacity memory store
STM encoding
Acoustic(sound)
STM capacity
Between 5 and 9 items on average
STM duration
About 18 seconds
Long-term memory
The permanent memory store
LTM encoding
Semantic (meaning)
LTM capacity
Unlimited
LTM duration
Up to a lifetime
Coding
The format information is stored in the various memory stores
Capacity
The amount of information that can held in a memory store
Duration
The length of time information can be held in a memory store
What is the process of converting information between different forms
Coding
Who researched coding?
Alan Baddeley in 1966
In Alan Baddeley’s research, what were the four groups of participants given to remember?
- Acoustically similar words - words that sound the same
- Acoustically dissimilar words - words that sound different
- Semantically similar words - words with similar meanings
- Semantically dissimilar - words with different meanings
What were the results of Alan Baddeley’s research?
when recalling from STM, participants did worse with acoustically similar words
When recalling LTM (after 20 mins), they did worse with semantically similar words
What did Alan Baddeley’s findings suggest?
Information is coded acoustically in STM and semantically in LTM
What are the strengths of Alan Baddeley’s study?
It identified a clear difference between two memory stores
It was an important step in understanding memory, which lead to the multi-store model
What are the weaknesses of Baddeley’s study?
There are some exceptions to his findings
The stimuli were artificial and unmeaningfull, so his findings do not tell us much about coding in different kinds of memory tasks, especially everyday tasks. This suggests his findings have limited real world applications, therefore low external validity
Who researched capacity?
Joseph Jacobs in 1887
Describe Joseph Jacobs digit span study
The reseracher would reas oyt 4 digits and the participants would recall them out loud in the correct order. If this is correct the reserafcher reads out five digits, adding one more digit each time until the participants cannot recall the order correctly. This was the digit span
What did Joseph Jacobs study find?
The mean digit span was 9.3. The mean span for letters was 7.3
What are the strengths of Jacobs’ study?
It has been replicated, showing that it is a valid test of digit span in the STM
What are the weaknesses of Jacobs’ study?
He may have overestimated the capacity of the STM. Nelson Cowan concluded that the STM has a capacity of about 4
Who researched capacity (span of memory and chunking)?
George miller in 1956
What did Geroge Miller observe?
Everyday practise
What observations did George Miller make?
Many things come in 7s-7 days of the week, 7 notes of a music scale
What did Miller decide from his research?
The capacity of the STM is about 7 +/- 2 items
Who researched duration of the STM?
Margaret and Lloyd Peterson in 1959
Describe the Petersons’ study
They tested 24 students in 8 trials. In each trial, the student was given a consonant syllable to remember. They were also given a 3-digit number. The student counted backwards form this number until they were told to stop. On each trial they were told to stop after varying periods of time, after 3,6,9,12,15 or 18 seconds (the etention interval time)
What were the results of margaret and lloyd peterson’s study?
After 3 seconds, the averae recall was about 80%
After 18 seconds, the average recall was about 3%
What did the Peterson’s study suggest?
The STM duration is about 18 seconds
What was the use of counting backwards in the Petersons study?
To prevent any mental rehearsing of the sonsonant syllable, which would increase the duration of the STM
What are the weaknesses of the Petersons study?
The stimuli material was artificial, so they lacked mundane realism and external validity
Who reserached the duration of the LTM
Harry Bahrick et al in 1975
Describe Harry Bahrick’s study
392 American aged between 17 and 74 were shown their year book and were tested on:
- Photo-recognition, tested on 50 photos, some from the participants high school yearbook
- Free recall, tested on their recall of all of the names of their graduating class
What were the results of Harry Bahrick’s study?
Participants tested within 15 years of graduation were about 90% accurae in photo recognition, and 60% in free recall. Participants tested 48 years after graduation were about 70% accurate in photo recognition, and 30% in free recall
What does Harry Bahrick’s study suggest?
The LTM may last up to a lifetie for some material
What are the strengths of Bahrick’s study?
It has high external validity, because meaningful memories were investigated, reflecting a more real estimate of the duration of the LTM
