Lesson 2 - STM And LTM Flashcards
What is visual encoding
These are memories stored visually
What is acoustic encoding
Memories stored based on what they sound like
What is semantic encoding
Memories stored based on a meaning e.g acronym
Baddeley - how is info coded - study of recall
- ppts given different lists of words to remember and asked to recall them (either immediately following presentation or after a longer time) in correct order
1. Acoustically similar
2. Acoustically dissimilar
3. Semantically(meant) similar
4. Semantically dissimilar
What were baddeleys findings on how Info is coded through recall?
Immediate recall - acoustically similar had worst recall, therefore STM coded acoustically
Delayed recall - second condition where ppts had to wait 20 min before recall, semantically similar words had the worst recall therefore LTM coded semantically
Expand on the evaluation of coding in STM/LTM
1. STM may not be exclusively acoustic
-some experiments have shown visual codes also used in STM
Bandimote - p’s use visual coding in STM if given a visual task and prevented from doing any verbal rehearsal in retention interval
Nelson and Rothbart - found evidence of acoustic coding in LTM - coding in STM and LTM not simply acoustic or semantic but can vary according to circumstances
Expand of the evaluation of coding in STM/LTM
2. Baddeley may not have tested LTM
-STM was tested by asking P’s to recall immediately - LTM tested by waiting 20 min but its questionable as to whether this is really testing LTM
Capacity - Immediate digit span study - Jacob’s
-ppts has to repeat back a string of numbers and letters presented to them in the same order and the number increased gradually until failure
Findings - ppts had an average span of 7.3 letters and 9.3 numbers
Miller - findings on capacity - everyday groups
Everyday observations - things come in groups e.g 7 notes on a musical scale. He observed everyday practice to see whether people group sets of letters/numbers into meaningful units
-proposed capacity of STM is 7(+/-2) but can be improved by chunking
Expand on this evaluation of capacity of STM
1. The capacity of STM may be even more limited
Cowan - reviewed variety of studies on capacity and found STM likely to be limited to four chunks
-research on capacity of STM for visual info also found four items was limit which means lower range of millers range is more appropriate
Expand on this evaluation of capacity of STM
2. The size of chunks matters
Simon - capacity can be increased if info is chunked. He tested his own immediate digit span and found length of chunking effected capacity - larger chunks more difficult and constantly found his digit pan to be 5 chunks
Expand this evaluation on capacity of STM
3. Individual differences
-capacity of STM not same for everyone as Jacob’s also found that recall increased steadily with age (possibly due to gradual increase in brain capacity)
Anokhin - estimated possible neuronal connection in brain is 1-10.5 million Km. concluded no human can can use full potential thus limit estimations of capacity of LTM are not accepted
Trigram retention experiment - Peterson and Peterson
-students given consonant syllables in trios to remember and were asked to count backwards from a particular number for 3-18 seconds depending on the conditions to prevent rehearsal
Bahrick et al - graduates longitudinal study
-high school graduates tested over a 50 year period
-shown yearbook photos and asked to recall names (free recall) or had to match names (regognition)
Recognition - 90% accurate 15 years - 70% after 48 years
Free recall - 60% after 15 years and 30% after 48 years
Expand this evaluation of duration of memory
1. Testing STM was artificial
-memorising consonant syllables doesn’t replicate real life as we try remember meaningful things. But sometimes we do try remember meaningless things such as phone numbers
