Lesson 2 - coding, capacity and duration Flashcards
coding in short term memory study
baddeley
list A - words sounded similar, list B - words sounded dissimilar, list C - words had similar meanings, list D - words had dissimilar meanings
list A was worse than list B
no difference between list C and D
so STM organises info acoustically, so similar words get muddled
coding in long term memory study
baddeley
repeated STM experiment but tested recall after 20 min delay
recall of C was worse than recall of D
no difference between list A and B
LTM is coded semantically - organised by meaning so words with similar meanings get confused
strength of baddeleys coding experiment
lab experiment
easy to replicate
variables closely controlled
reliability can be assessed
weakness of baddeleys coding experiment
low ecological validity
material for recall was artificial
lab setting is also artificial
capacity of STM study
jacobs - digit span test
pps given sequences of digits/letters
asked to repeat sequence immediately after in correct order and sequence increased by one each time
concluded we can hold 9 digits and 7 letters
what did miller conclude
span of STM is 7+/- 2
if we recall more info than we have capacity for, new info displaces old info
people can recall 5 words as easily as 5 letters
chunking helps remember more
strength of jacobs study
study has been repeated and same results found
study has validity
weakness of jacobs study
conducted a long time ago
may not to have been done to the same scientifically rigorous standard as research today
validity of findings in question
duration of STM study
peterson and peterson
nonsense consonant trigrams
used maintenance rehearsal - pps count back in 3s
3s - 90% accuracy
9s - 20% accuracy
18s - 2% accuracy
STM lasts for 18-30s and is then lost due to decay
strength of peterson and petersons study
used fixed timings
eliminated noise and other factors which could influence memory
high level of control using standardised procedures
weakness of peterson and petersons study
findings may be due to interference rather than short duration
earlier learnt trigrams may be confused with later ones
duration of LTM study
bahrick - 400 people age 17-74 tested memory of their classmates
link names and faces - 70% accuracy
free recall - 30% accuracy
lasts a lifetime
but retrieval failure occurs and retrieval cues needed to access information
strength of bahricks study
higher ecological validity
tested meaningful material relevant to everyday life
weakness of bahricks study
natural experiment
difficult to control extraneous variables
some people may still be in touch or have looked in their yearbook since leaving school