The Capacity, Coding and Duration of STM and LTM - 05/12/23 Flashcards
What does Coding mean?
The format in which info is stored in the various memory stores
What does Capacity mean?
The amount of info that can be held in a memory store at a given time
What does Duration mean?
How much time information can be held in a memory store
What is Short Term Memory (STM) and what are it’s properties?
- The limited capacity memory store
- Coding is mainly acoustic
- Capacity is between 5-9 items
- Duration is between 18-30 seconds
What is Long Term Memory (LTM)?
- The permanent memory store
- Coding is mainly semantic
- Unlimited Capacity
- Unlimited store of memories
What are the Research Studies for Short Term Memory?
- Baddeley- Coding
- Jacob/Miller - Capacity
- Peterson and Peterson - Duration**
What are the Research Studies for Long Term Memory?
- Baddeley - Coding
- Duration - Bahrick
x
Desribe Baddeley’s study. (Aims, Procedure, Findings, Conclusions)
- Aims- Assess whether coding in STM was mainly semantic or acoustic
- Procedure - Uses word lists like cat, mat. There were 4 sets of word lists - acoustically similiar, acoustically dissimilar, semantically similiar, semantically dissimilar. Participants had to recall order of word lists. Done immediately to assess STM, 20 min after to assess LTM
- Findings - Participants given list of acoustically similiar words had worst recall. Confused similiar sounds word. Participants given list of semantically similiar words had worst recall.
- Conclusion - Poor recall showed words were confused. For immediate recall, acoustically sounding words weren’t remembered well. Suggests STM is acoustically coded, people remembered other lists fine. For delayed recall, semantically sound words weren’t remebered well. LTM is semantically coded**
Desrcibe Jacobs (1887) Study.
- Aims- Research capacity of STM
- Procedure - Developed technique to measure digit span - how many items an individual can remember in sequence and repeat in order
- Findings - Found mean span for digit was 9.3 items. For letters it was 7.3
- Conclusion - Memory can hold 7-9 items**
Describe Miller (1956) study.
- Aim - Research capacity of STM
- Procedure - Saw things came in sevens (days of week). Chunked items into groups
- Findings - Found people could recall 5 words, and 5 letters
- Conclusion - Used term ‘magical number 7’ to describe capacity***
Desribe Peterson and Peterson (1956) study.
- Aim - Research duration of STM
- Procedure - 24 students did 8 trials and were given consonant syllable (BNT) and a three-digit number and asked to count back down to stop rehearsal
- Findings - STM lasts 18s after this hard to recall
- Conclusion - STM has a very short duration, unless rehearsed**
Describe Bahrick (1975) study.
Aim:
Research duration of LTM
Procedure:
Tested recall of people participants had gone to school with using photo recognition and free recall
Findings:
90% accuracy for photo recog with people who graduated in 15 years and 60% accuracy for free recall. After 48 years, photo recog = 70% and other 30%
Conclusion:
LTM lasts a long time
Baddeley
What is a Limitation of the Research into Capacity, Coding and Duration of STM and LTM?
- Baddeley’s study didn’t have any meaningful material
- Words had no personal meaning
- When info is meaningful people will use semantic coding even in STM
Jacob (too old)
What is a Limitation of the Research into Capacity, Coding and Duration of STM and LTM?
- Jacob’s study was conducted a long time ago
- Early research lacked control of extraneous variables
- Some participants = distracted
- Reduces validity of finding
Miller (oversimplified)
What is a Limitation of the Research into Capacity, Coding and Duration of STM and LTM?
- Miller’s research may have oversimplified capacity in STM
- Cowan (2001) reviewed other research and said that capacity of STM was only 4 chunks lower than 5-9 itms
- Accepted capacity of STM = inaccurate
