Coding, capacity and duration of memory Flashcards
Coding
the process of converting information from one form to another
What did Alan baddeley do?
gave different lists of words to four groups of participants to remember and asked them to recall them in order
Baddeley group one
- acoustically similar
- words sounded similar
Baddeley group two
- acoustically dissimilar
- words sounded different
Baddeley group three
- semantically similar
- words with similar meaning
Baddeley group four
- semantically dissimilar
- words that all had different meanings
What did Baddeley find?
- when participants had to do the recall task immediately after hearing it (STM recall), they tended to do worst with acoustically dissimilar words
- if participants were asked to recall the words after a time interval of 20 mins, they did worse with the semantically similar words
What did Baddeleys findings suggest about coding in long term memory?
information is coded semantically In long term memory
What is a limitation of Baddeleys study?
- it used artificial stimuli rather than meaningful material as the word lists had no personal meaning to participants
- this means we should be cautious about generalising the findings to different types of memory tasks
- e.g. when processing more meaningful information, people may use semantic coding even for STM tasks
- suggests that the findings have limited application
capacity
the amount of information that can be held in a memory store
What did Jacobs do?
- developed a technique to measure digit span
- e.g. the researcher gives the participants 4 digits to recall these in the correct order out loud. if this is correct, the researcher reads out 5 digits and so on until the participant cannot recall the order correctly
- this determines the individuals digit span
What did Jacobs find?
- the mean span for digits across all participants was 9.3
- the mean span for letters was 7.3
What did Miller do?
- made observations of everyday practice
- e.g. he noted that things come in sevens: 7 notes on musical scales, 7 days of the week, 7 deadly sins
What did the number 7 mean in the study Miller?
-suggested that the capacity of STM is 7(+/-2)
What did Miller find?
- people can recall 5 words as well as 5 letters
- they do this by chunking, grouping sets of digits or letters into units or chunks
What is a limitation of Jacob’s study?
- it was conducted a very long time ago
- early research into psychology often lacked adequate control
- e.g. some participants may have been distracted while they were being tested so they didn’t perform as well as they might of done
- means that the results may not be valid because there were confounding variables that were not controlled
- however results of this study have been confirmed in other research supporting its validity
What is a limitation of Millers study?
- Miller may have overestimated the capacity of STM
- Cowan reviewed other research and concluded that he capacity of STM was only 4 chunks
- suggests that the lower end of millers estimate (5 items) is more appropriate than 7 items
Duration
the length of time information can be held in memory
what was Peterson and Peterson study?
duration of STM
- the student was given a consonant syllable to remember and was asked to count backwards from a 3 digit number
- counting backwards was to prevent any mental rehearsal of the consonant syllable
- on each trial, they were asked to stop after a different amount of times 3,6,9,12,15 or 18 seconds - called the retention interval
What did Peterson and Peterson find?
-STM may have a very short duration, unless we repeat something over and over again
What is a limitation of Peterson and Peterson’s study?
- the stimulus material was artificial
- trying to memorise constant syllables does not reflect most real life memory activities where what we try to remember is meaningful
- therefore this study lacked external validity
What was Bahrick et al study on duration of LTM?
- studied 392 participants from Ohio aged from 17 to 74
- participants were given a photo recognition test from their high school yearbook consisting of 50 photos
What did Bahrick et al find?
- participants who were tested within 15 years pf graduation were approx 90% accurate in photo recognition
- After 48 years, recall declined to 70%
- shows that LTM lasts a long time
What is a strength of Bahrick et al study?
- higher external validity as real life memories were studied
- when studies have been conducted on meaningless pictures to be remembered, recall was lower
