features of memory Flashcards
what is memory
the process by which we retain and recall information about events that have happened in the past
what is short term memory
your memory for immediate events, which disappears if not rehearsed
what is long term memory
your memory for events that have happened in the past from anywhere between 2 mins and 100 years ago. it is the permanent memory store
what is the sensory register
stores a large amount of information from our senses for a very brief amount of time (half a second)
what is capacity of memory
the amount of information that can be held in a memory store
what is the duration of memory
the length of time information can be held in the memory store
what is coding of memory
the format in which information is stored in the memory stores. Its the process of converting information from one format to another
what is acoustic coding
information stored in the form of sounds
what is semantic coding
information stored in the form of the meaning of the experience
outline Jacobs (1887) study
- capacity
- participant is given 4 digits and asked to recall them correctly
- number of digits increases until participant gets it wrong
- determines individual’s digit span
- mean digit span is 9.3
- mean letter span is 7.3
Jacob’s study evaluation
- conducted a long time ago so lacked control (CV/EVs)
- valid because results have been supported by other research
Outline Miller’s (1956) study
- human memory capacity is 7 items(+/- 2)
- people memorise chunks of letters/numbers
- Cowan disagrees- Miller may have overestimated capacity of STM- it may be 4 chunks - so lower end of Miller’s estimate is correct
Capacity of LTM
potentially unlimited
Duration of STM
up to 30 seconds without rehearsal
(Peterson and Peterson)
outline Peterson and Peterson’s study
- participants given trigrams to memorise
- participants given a 3 digit number and told to count backwards from the number in 3s until stopped (for 3,6,9,12,15,18s)
- participants asked to stop counting and repeat the trigram
- the longer the interval, the less trigrams recalled correctly
- STM has a limited duration (up to 30s) when rehearsal is prevented
evaluation of Peterson and Peterson’s study
- artificial stimuli so not externally valid as we dont typically try to memorise useless information so duration of STM may be underestimated
- however we do sometimes try memorise meaningless information (e.g. phone numbers) so study is not completely irrelevant
- controlled- same length and difficulty for participants so greater internal validity to see duration of STM without rehearsal
Duration of LTM
potentially up to a lifetime
(Bahrick et al.)
Outline Bahrick et al’s(1975) study
- within 15 years of graduation, recognise 90% and after 48, recognise 70%
- free recall within 15 years is 60%, within 48 years is 30%
Evaluation of Bahrick et al’s study
- high external validity as real-life photos were studied
- CVs are not controlled e.g. participants may have looked at yearbook photos over the years and rehearsed their memory so lacks internal validity
how is STM coded
acoustically (Baddeley)
how is LTM coded
semantically (Baddeley)
Outline Baddeley’s study (1966)
-4 groups- acoustically similar, acoustically dissimilar, semantically similar, semantically dissimilar
- recall task immediately- worse recall of acoustically similar words
- recall task after 20 minutes- worse recall of semantically similar words
Baddeley’s study evaluation
- words were artificial stimuli rather than meaningful material so study isnt generalisable e.g. when processing meaningful information, the coding of STM and LTM may be different
