Coding, capacity and duration of memory Flashcards
Who conducted research on coding and when?
Baddeley in 1966
What was Baddeley’s research on coding?
Lists of words were given to groups of participants which were semantically similar, semantically dissimilar, acoustically similare or accoustically dissimilar. When recalling immediately, they were worse at accoustically similar words but after 20 minutes, they did worse with semanticallt similar words. This suggests that LTM is coded semantically and STM is coded acoustically.
What did Jacobs investigate?
He did research on capacity by measuring digit span. 4 digits were given and if they were recalled correctly, 5 digits were then given and so on. This determines an individuals digit span. The mean span for digits was 9.3 and the mean span for letters was 7.3.
What did Miller do?
He looked at the span of memory and chunking and suggested the capacity of STM is 7+- 2 items. He also said people can remember 5 words as well as they can five letters by chunking.
Who did research on the duration of STM?
Peterson and Peterson in 1959
What experiment did Peterson and Peterson carry out?
24 undergraduate students took part in trials where they were given consonant syllables to remember and were asked to count backwards from a number to prevent mental rehearsal. They were told to start after intervals of 3, 6, 9, 12, 15 and 18 seconds and found that after 3 seconds over 75% of responses were correct but after 18 seconds around 12.5% were correct. This shows that LTM has a short duration.
What experiment did Bahrick et al carry out?
High school yearbooks were used and were asked to recall the names of people in their class or to pick out the class mates from 50 pictures of people. 15 years after graduation, there was 90% accuracy in photo recognition and 60% accuracy in free recall but 48 years after graduation photo recognition was 70% accurate and free recall was only 30% accurate. This shows LTM can last a very long time.
What is a limitation of Baddeley’s study?
It used artificial stimuli, meaning it is difficult to generalise to other memory tasks.
What is a limitation of Jacob’s study?
It was conducted in 1887 and so lacks validity as it was carried out so long ago and experiments weren’t as controlled.
What is a limitation of Miller’s study?
He may have overestimates the capacity of STM as Cowan reviewed research and concluded the capacity was only four chunks, not the 7 Miller estimated.
What are the limitations of Peterson and Petersons studies?
The stimuli were meaningless and so it lacks external validity.
It ignores diplacement as an explanation for forgetting as when they count down, they are replacing the information.
What is a strength of Bahrick’s study?
It has high external validity as real life memories were studied, although this leads to more confounding variables.
