Memory: Lesson 2 - Coding, Capactiy, Duration Flashcards
How information coded in the Sensory Register?
Coding in the SR is modality specific
Modality specific = each sensory story (e.g. iconic for visual information) codes differently
How is information coded in the Short-Term Memory?
Acoustically
What study proves that information is coded acoustically in the STM?
Baddeley (1966)
- gave participants 4 lists of words to recall
- List A contained words that sounded similar; list B had = dissimilar; list C = similar meanings; list D = dissimilar meanings
- Baddeley argued that STM is coded acoustically b/c participants performed worse with list A than list B, but there was no difference between list C and D
- words in STM are organised based on how they sound, so similar words get muddled
How is information coded in the LTM?
Semantically
What study proves that information is coded semantically in the LTM?
- Baddeley (1966)
- tested participant’s recall of the lists after a 20 minute delay to ensure the information had passed into LTM
- Participant’s recall of list C was worse than their recall of list D
- no difference between list A and list B
- Baddeley concluded that LTM is coded semantically and that it organises information according to its meaning, so words with similar meaning can become confused.
What is the capacity of the Sensory Register?
Unlimited
What is the capacity of the Short Term Memory?
7 (+/-) 2
What study suggests that the STM has a capacity of 7 (+/-) 2?
Jacobs (1887)
- used a digit span test to determine capacity
- gave participants several sequences of digits or letters, asking them to repeat each sequence immediately after he had given it, in the correct order
- sequences got longer by one item each time
- found that on average we can hold 9.3 digits and 7.3 letters
- Miller (1956) reviewed psychological research and concluded that the span of STM is 7 (+/) 2
- If we try to recall more information than we have the capacity for then new incoming information displaces old information
- also found that people can recall five words as easily as five letters (chunking), which helps us remember more
What is the capacity of the Long-Term Memory?
Unlimited
What is the duration of the Sensory Register?
250 milliseconds
What is the duration of the Short-Term Memory?
18-30 seconds
without rehearsal, and then it is lost to decay
What study suggests that the STM has a duration of 18-30 seconds?
Peterson & Peterson (1959)
- used nonsense trigram’s (random 3 consonants) to test STM duration
- asked participants to count backwards from 100 in threes to prevent them keeping the information in STM using maintenance rehearsal
- After 3 seconds recall was accurate 90% of the time; after 9 seconds they were accurate 20% of the time; but after 18 seconds it was only accurate 2% of the time
- concluded that information in STM lasts for 18-30 seconds without rehearsal, before it is lost due to decay
What is the duration of Long-Term Memory?
Potentially a lifetime
but sometimes retrieval failure takes place and retrieval cues are needed
What study suggests that the duration of LTM is potentially a lifetime?
Bahrick (1979)
- tested 400 people of various ages (17-74) on their memory of their classmates.
- A photo recognition test consisted of participants being shown 50 photos and deciding if they belonged to their classmates or not
- In a free recall test participants were asked to list the names they could remember from their graduating class
- 90% accuracy at identifying faces of school friends within 15 years of leaving school
- 70% accuracy after 48 years
- Free recall of names of classmates was 60% accurate within 15 years of leaving school, dropping to 30% after 48 years
- concluded that the duration of LTM is potentially a lifetime but sometimes we have retrieval failureand need retrieval cues in order to access this information
