2.5 (research demonstrating capacity)

capacity

sensory memory: untested, but believed to be unlimited

short term: 5 - 9; 6 letters, 5 words

long term: unlimited

duration

iconic: < 1 second

echoic: < 4 seconds

ST: < 12 seconds without rehearsal

LT: stable across the lifetime

studies

sensory: sperlings partial report

short term: digit span test

long term: Ebbinghaus forgetting curve

Sperlings partial report

whole report: given a 4 x 3 grid of letters and asked to remember all (3 - 5 were generally recovered)

Partial report: 3 x 3 grid of letters and asked to recite one line at random - 75% remembered all 3 no matter which line

digit span test

a series of numbers is read to subjects who are then asked to recall the numbers in order- the success rate was 50% for 7 digits and dropped significantly after 9

Ebbinhaus' forgetting curve

The course of forgetting is initially rapid, that levels off with time (he used nonsense syllables to ensure he wouldn't encode with meaning)

where are explicit memories stored

throughout the cerebral cortex in semantic networks

Henry Molaison

removal of hippocampus, could not commit anything to long term memory (implicit memories were not affected)

Anterograde vs retrograde amnesia

Anterograde: inability to encode new memories due to damage to the hippocampus

Retrograde: inability to recall past memories due to damage to some part of the cortex

global amnesia is when we have both