Memory Flashcards
What is STM?
Allows us to recall memory from up to 30s ago. Is very limited.
What is LTM?
Enables us to recall memory from distant past, has unlimited capacity and has potentially a lifetime of duration.
What are the 3 ways that STM and LTM differ?
- duration
- capacity
- encoding
What is duration?
How long information can be stored for/ how long it lasts.
What’s STM’s duration?
Doesn’t last long.
To keep info for longer than a few seconds it must be rehearsed to be kept active.
What’s the STM duration study?
Peterson and Peterson,
24 undergrad students given constant trigram.
Asked to count backwards in 3s (to stop them from rehearsing it)
Then asked to stop and repeat trigram.
Repeated using different trigrams
What were Peterson and Peterson’s results?
90% after 3s.
20% after 9s.
Less than 10% after 18s.
What was the conclusion of Peterson and Peterson’s study?
Information decays quick when you can’t rehearse it.
Maximum duration of STM is 18s
What are the positives of Peterson and Peterson experiment?
+ Lab experiment, tightly controlled variables can be replicated to see if results are reliable
What are the negatives of Peterson and Peterson study?
- Low ecological validity is unrealistic
- trigrams from earlier trials can cause confusion. Results gained can be due to participants forgetting or being confused
What is the overall conclusion of STM maximum duration?
18 to 30 seconds without rehearsal (due to further research)
What is LTM duration experiment?
-Bahrick et al (1975)
-400 Americans
-asked how well they could remember former classmates:
Matching names to pics or recalling names with no picture cue
What were the results from Bahrick’s study?
- 70% accuracy from after 48 years using the link/Cue
- 30% accuracy from after 48 years (free recall names)
What is the conclusion from the long-term memory duration study?
30 to 50 years on people are still able to recall, long-term memory can last a lifetime.
- Cannot immediately access info in LTM
- cues being presented help with retrieval
What are the positives and negatives of Bahrick’s study?
+High ecological validity is as it was a natural task
- less control of the independent variable as it’s likely some of the names could have been rehearsed
- only looked at a specific type of information, type of info is particularly meaningful and regularly rehearsed
What is capacity?
Measure of how much information can be held/stored.
LTM probably unlimited
STM very limited
What is the experiments for STM capacity?
Jacobs (1887)
Serial digit span technique, four digit number was read and asked to repeat
Digit added to participant couldn’t repeat accurately
What are the results of Jacobs study?
-9 digits and 7 letters correctly recalled.
-capacity increased with age during childhood:
-gradual increases in brain capacity
-ppl developed strategies to improve it (chunking)
Digits are easier to remember as theirs only 10.
What’s the STM capacity experiment evaluation?
- lacks ecological validity as it’s an unrealistic test.
- can’t be sure of extraneous variables were controlled as it was done so long ago.
What did miller say?
STM has capacity of 7+-2 items.
Capacity can be increased by chunking.
Size of chunk is important.
What did cowen argue with miller about?
He aid miller may have overestimated capacity of STM after reviewing research.
What is coding?
Form in which information is stored in memory
What are the different types of coding?
- acoustic-by the way it sounds
- semantic-by the terms of its meaning
- visual-by the way it looks
How is information encoded in stm?
Acoustic form
How is info stored in LTM?
Semantically (on basis of meaning)
What conclusion can we draw from how information is stored in the STM and the LTM?
Acoustically similar words are harder to remember, and we are more likely to make mistakes remembering semantically similar words.
What was baddelys experiment?
Five words under 1/4 conditions: -acoustically similar words -acoustically dissimilar words -semantically similar words -semantically dissimilar words. And then immediately had to write them down in order
What were the results of Baddeley experiment?
Participants were least accurate with acoustically similar words (they’ve got muddled)
20 minutes later participants well least accurate with semantically similar words.