Memory Flashcards
What are the three important stores in our memory?
Sensory memory, LTM and STM
What is the duration of our memory?
How long the information stored lasts
What is the capacity?
How much information our memory can hold
What is the encoding of our memory?
How information enters our brain and the format in which it is stored
Who was the duration of STM investigated by?
Peterson and Peterson
What was the method of Peterson and Peterson’s STM duration study?
- 24 students were presented with nonsense trigrams, followed by a 3 digit number
- Participants were than asked to recall the trigrams after increasing lengths of time
In Peterson and Petersons duration study, what did they ask participants to do to prevent them from rehearsing the trigrams?
Count backwards from a certain number
What were Peterson and Petersons findings?
After a 3 second interval, there was 90% recall. But after 18 second interval, there was only a 2% interval
What can we conclude from Peterson and Petersons STM duration findings?
If there is no verbal rehearsal, the duration of the STM is less than 18 seconds
What is the duration of STM?
Less than 18 seconds if no verbal rehearsal
What is the capacity of STM?
7 +/- 2 chunks of information
What did Miller find in his experiment into the capacity of short term memory?
Participants can cope reasonably well in counting 7 dots when flashed onto a screen, but not many more
According to Miller, how can we increase the capacity of STM?
If we chunk information together into groups
What did Jacobs use to assess the capacity of STM?
The digit span technique
What did Jacobs find regarding the capacity of the STM?
Average span for digits was 9.3, average span for letters was 7.3
What was the method of Baddelys experiment regarding the encoding in LTM & STM?
Participants were given a list of words that were either acoustically similar or dissimilar, or semantically similar or dissimilar
What were the findings of Baddelys encoding experiment?
Participants had more difficulty remembering acoustically similar words in STM but not LTM, but participants found it easier remembering semantically similar words in the STM
What is the encoding in STM and LTM according to Baddelys experiment?
Encoding in STM is acoustic. Encoding in LTM is semantic.
What was the method of Bahricks natural experiment regarding the duration of long term memory?
392 participants of various ages were shown pictures from their high school yearbooks and asked to put faces to names
What were the findings of Bahricks LTM duration experiment?
More than 48 years later, participants were 70% accurate in putting faces to names
Why might there be such a high accuracy in Bahricks LTM duration study?
Due to the meaningful material used
What was the method of Shepards LTM duration experiment?
Participants were shown over 600 memorable pictures, one by one. A few hours later the images were shown again within a set of others
What were the findings of Shepards LTM duration experiment?
Hours later, there was almost perfect recognition. 4 months afterwards, participants were still able to remember 50%
What is the capacity of LTM?
Potentially unlimited
Evaluation of the research into the duration of STM?
- Lacks ecological validity as artificial stimuli was used in artificial settings
- Demand characteristics; participants may guess aim
- Similar study where Ps were tested without warning: forgetting occurred after 2 seconds showing STM duration may be shorter
Evaluation of research into STM Capacity?
- Capacity may be more limited: 4 chunks
- Individual Diffs
- Jacobs study: digit span increased with age, maybe due to increase in brain capacity
Evaluation of research into STM/LTM encoding?
-Lab experiment conducted that found that STM may sometimes use other codes
Evaluation of research into LTM duration?
- Generalisability: difficult to find tasks only representing LT memories
- Participants may have seen classmates or looked at yearbook explaining high levels of recall
Why did Peterson and Peterson ask participants to count backwards out loud before recall?
To prevent verbal rehearsal
What are two limitations of the research into STM capacity?
1) capacity may be even limited, it has been suggested that it is four chunks
2) individual doffs: in Jacobs study, the digit span increased with age which could be due to an increase in capacity
