Coding, Capacity and duration Flashcards
Define coding
Converting information between different forms
Describe Baddeleys research on coding
- Baddely gave different lists of words to four groups of participants to remember:
Group 1 had acoustically similar words, group 2 had acoustically dissimilar words, group 3 had semantically similar words and group 4 had semantically dissimilar words - These participants were aked to recall them in the correct order. When they did this task immediately with STM they did worse with semantically similar words
- They then did this after an interval of 20 minutes, recalling from LTM and did worse with semantically similar words
What does Baddeley’s research suggest?
It suggests that information is coded acoustically in STM and semantically in LTM
What is capacity?
How much information that can be held in a memory store
Describe research on digit span
Jacobs (1887) measured digit span. For example, he would read out 4 digits and have the participant to recall them in the correct order. If they got them correct they would do 5 digits
What were the findings of Jacobs
Jacobs found that the mean span for digits was 9.3 items. The mean span for letters was 7.3.
Describe research on the span of memory and chunking
George Miller (1956) made observations of everyday practices and found things normally came in 7s. For example, 7 days of the week
What were the findings of Miller
The span of STM is about 7 items plus or minus 2. But he also noted that people chunk sets of digits or letters into units or chunks
Describe the research on the duration of STM
- Magaret and Lloyd Peterson (1959) tested 24 students in eight trials. They gave each participant a 3 digit number and 3 letters and asked them to count backwards to prevent mental rehearsal. They were told to stop at varying times such as 3,6,9,12 seconds
What were the findings of Magaret and Llyod pertersons research
after 3 seconds, recall was 80% seconds whereas after 18 seconds recall was 3%. This shows the duration of STM is about 18 seconds
Describe the research on the duration of LTM
Bahrick et al (1975) studied 392 American participants aged between 17 and 74 and used their highschool year books.
- this was done through photo recognition or free recall of all the names of their graduating class
What were the findings of Bahrick
- participants tested within 15 years of graduation were 90% accurate with facial recognition and 60% with free recall
- after 48 years, 70% for facial recognition and 30% with free recall
Evaluate Baddeleys research
Strength = it identified a clear difference between two memory stores and has stood the test of time
Weakness = Used artificial stimuli and the lists of words had no meaningful meaning to participants
Evaluate Jacobs and Millers research
Strength = Jacobs study has been replicated and have been confirmed by other more controlled studies such as Bopp. This shows it is valid
Limitation = Miller may have overestimated STM capacity. Cowan (2001) reviewed researched and showed the capacity of STM is about 4 plus or minus chunks
Evaluate the Petersons and Bahricks research
Limitation of petersons research = The stimulus material was artificial. The syllables and numbers were not reflective of the everyday memory activities of people
Strength = Bahricks study has high external validity as it tested meaningful memories and is a real estimate of memory
