Coding, capacity and duration of memory Flashcards
What is coding?
Coding is the process of converting information between different forms
Explain the process of Baddeley’s study
He gave different lists of words to four groups of participants to remember
- Group 1 (acoustically similar) e.g. cat, cab, can
- Group 2 (acoustically dissimilar) e.g. pit, few, cow
- Group 3 (semantically similar) e.g great, big, large
- Group 4 (semantically similar) e.g good, huge, hot
Ps were shown the original words and asked to recall them in correct order
What were the findings of Baddeley’s experiment?
When ps did this task immediately, recalling from STM, they tended to do worse with acoustically similar words
When they recalled the word list after a time interval of 20 mins, recalling from LTM, they did worse with semantically similar words
What do Baddeley’s findings suggest?
Information is coded acoustically in STM and semantically in LTM
What is capacity?
Capacity is the amount of information that can be held in a memory store
How did Joseph Jacobs measure capacity of the STM
He measured digit span- he read out four digits and the ps recalled them out loud in the correct order, each time adding on an extra digit to recall, until they could no longer correctly recall the numbers
What was the mean span for digits and letters that were correctly recalled
Digits- 9.3
Letters- 7.3
What did Miller think the span of the STM is
7 ±2
(5-9)
He suggested that we remember letters and digits by chunking
What is Duration?
The length of time information can be held in memory
How did Margaret and Lloyd Peterson measure duration of STM?
- They tested 24 students in 8 trials each
- each trial the student was given a consonant syllable to remember (YCG) and a 3 digit number
- the student counted backwards from this number until told to stop
- on each trial they were told to stop after varying periods of time (3,6,9,12,15, or 18 secs)
What were the findings of the Petersons’ study
After 3 secs average recall was about 80%
After 18 secs it was about 3%
What do the Petersons’ findings suggest about the duration of the STM?
STM duration may be about 18 secs unless we repeat the information over and over (verbal rehearsal)
How did Henry Bahrick et al research the duration of the LTM?
- they studied 392 American ps aged 17-74
- high school yearbooks we’re obtained from each p
1. Recall was tested using the photo recognition test consisting of 50 photos
2. Recall was tested using free recall test- ps recalled all the names of their graduating class
What were the findings of Bahrick et al’s study?
- Ps tested within 15 years of graduation were about 90% accurate in photo recognition
- After 48 years, recall declines to 70% for photo recognition
- free recall was less accurate than recognition: 60% after 15 years and 30% after 48 years
Therefore LTM may last up to a lifetime for some material
What is the strength of Baddeley’s study
it has identified a clear difference between the STM and LTM
