Short And Long-term Memory Flashcards
How are shot term memory and long term memory distinguished?
Capacity, duration and coding
What does capacity mean?
This is a measure of how much can be held in memory. It is represented in terms of bits of information, such as a number of digits
What does duration mean?
A measure of how long a memory lasts before it is no longer available
What does coding mean?
The way information is changed so that it can be stored in memory.
How does coding work?
• Information enters the brain via the senses (e.g. eyes and ears)
• It is then stored in various forms, such as visual codes (a picture), acoustic codes (sounds), or semantic codes (meaning of the experience)
What is the magic number and what does it mean?
7 ± 2
The span of immediate memory is seven items, give or take two.
What is the average span of digits and numbers in STM? How did Jacobs explain this?
• 9.3 items for numbers
• 7.3 items for letters
• Jacobs suggests it might be due to there only being 9 digits but 26 letters
Who studied short term memory?
Lloyd and Margaret Peterson (1959)
In the Petersons’ study, how many participants were there and what was the procedure?
• 24 students
• Each participant tested over 8 trials
• On each trial, a participant was given a consonant syllable and a three-digit number (e.g. THX 512)
• They were asked to recall the consonant syllable after a retentioj interval of 3, 6, 9, 12, 15, or 18 seconds
• During the interval, they had to count backwards from their three digit number
What were the findings of the Petersons’ study and what does this suggest?
• Participants on average were correct 90% after 3 seconds, 20% correct after 9 seconds, 2% correct after 18 seconds
• This suggests that the STM has a very short duration - less than 18 seconds as long as rehearsal has not occured
Who studied the duration of LTM?
Bahrick (1975]
How many participants were in Bahrick’s study and what was the procedure?
• 400 people of carious ages (17-74)
• A photo-recognition test on the memory of their classmates, consisted of 50 photos - some from highschool yearbook
• In a free-recall test participants were asked to list the names they could remember of those in their graduating class
What were the findings of Bahrick’s study on LTM?
• Photo recognition
- Participants tested within 15 years of graduation were ~90% accurate in identifying faces
- After 48 years this declined to ~70%
• Free recall
- After 15 year ~60%
- After 48 years ~30%
Who tested the effects of acoustic and semantic similarity on memory coding?
Baddeley (1966)
