MSMOM STM Flashcards
what is the STM?
-short term memory
-an active memory system
-temporarily stores info from the SR
how is info coded in the STM?
-arrives from the SR in its raw, unprocessed form, and is encoded into a form the STM can understand
-can be done in 4 ways
-visually (imagining the thing)
-acoustically (repeating the word of the thing)
-semantically (through meaning)
-research suggests the main form is acoustically
research on the coding of the STM
-Posner & Keele 1967 - p’s could faster assess that ‘A’ followed by ‘A’ were the same letter than if it was followed by ‘a’ since the visual codes differ, illustrating coding forms beyond acoustic
what was Baddeley’s classic research?
-1966
-75 p’s presented with one of four word lists repeated 4 times
-list A - acoustically similar (eg cat and mat)
-list B - acoustically dissimilar (eg pit, day)
-list C - semantically similar (eg big, tall)
-list D -semantically dissimilar (eg hot, safe)
-had to rearrange the words into the original order (20 minute gap for LTM study)
-for STM list A performed the worst (10%), the other lists were 60-80%
-for LTM list C performed the worst (55%), other lists were 70-85%
-seems there’s an acoustic confusion in STM
-seems there’s a semantic confusion in LTM
evaluate Baddeley’s research
-his findings make ‘cognitive sense’
-small difference between recall of semantically similar and dissimilar words (64 and 71%) in STM suggests there’s semantic coding
-lab study, shows cause and effect, but lacks ecological validity
-results can be replicated
evaluate the coding the of STM
-research shows coding is mainly acoustic, but other sensory codes are used, as some things can’t be coded acoustically
what is the capacity of the STM?
-limited, between 5-9 items
-capacity can be increased through chunking
research on the capacity of the STM
-Jacobs 1887 - serial digit span method, having to recall lists of numbers, when they failed on 50% they were said to have reached their capacity, found 9 items for numbers and 7 items for letters, has little relevance in real life though
evaluate the capacity of the STM
-other factors influence STM capacity, such as age or practice
-nowadays most STM limitations are seen as due to processing limitations associated with attention
what is the duration of the STM?
-limited, maximum 30 seconds
-can be extended with rehearsal (if done long enough the info will move to LTM)
research on the duration of the STM
-Peterson & Peterson 1959 - nonsense trigrams read to p’s, then asked to count backwards in threes from a large number (prevents repetition), found 90% of trigrams were recalled correctly after 3 seconds, only 5% after 18 seconds (could have a flawed methodology because different trigrams were used each time)
evaluate the duration of the STM
-Reitman 1974 suggests the brief duration is due to displacement (new info pushes out existing info)
-little research on other forms of stimuli, eg visual images
