Coding, Capacity and duration of memory Flashcards
Coding
The format in which information is stored in the various memory stores.
Capacity
The amount of information that can be held in a memory store at a given time.
Duration
The lengths of time information can be held in a memory store.
Short Term Memory
The limited capacity memory store. Coding is mainly acoustic, capacity is between 5 and 9 items on average, duration is between 18 and 30 seconds.
Long Term Memory
The permanent memory store. Coding is mainly semantic, it has unlimited capacity and can store memories for up to a lifetime.
Baddeley (1966)
aim: Researched coding in STM and LTM
procedure: Used word lists such as cat, mat, hat and chat in research on memory. There were 4 sets of word lists - acoustically similar, acoustically dissimilar, semantically similar, semantically similar, semantically dissimilar. Participants had to recall the word lists and this was done immediately to asses the STM and after 20 mins to assess LTM.
findings: Participants given the list of acoustically similar words had the worst recall. They confused the similar sounding words. Participants given the list of semantically similar words had the worst recall. They confused the similar meaning words.
conclusions: Poor recall, showed the words had become confused. For the immediate recall, acoustically sounding words were not remembered well. This suggests that STM is acoustically coded, bc ppl were able to remember the other lists of words fine. for delayed recall semantically sounding words were not remembered well. This suggests that LTM is semantically coded.
Jacobs (1887)
aim: research capacity of STM
procedure: developed a technique to measure digit span- how many items an individual can remember, in sequence and repeat back in order.
findings: found the mean span for digits across participants was 9.3 items. Found that the mean span for letters across participants was 7.3.
conclusion: memory can hold 7-9 items.
Miller (1956)
aim: research capacity of STM.
procedure: observed that things come in sevens: days of the week, notes on a music scale, deadly sins etc. Also used the diet span technique, but “chunked” items into groups e.g words and sets of numbers.
finding: found people could recall 5 words, as well as they can recall 5 letters (via chunking).
conclusion: used the term ‘the magical number 7’ to describe the capacity of STM.
Peterson and Peterson (1956)
aim: research duration of STM.
procedure: 24 students took part in 8 trials and were given a consonant syllable/ trigram such as BMT and a three-digit number and asked to count backwards to prevent reversal. On each trail, they they were stopped after either 3, 6, 12, 15 or 18 seconds.
findings: found that STM lasts about 18 seconds after this very few people correctly recall the consonant syllable.
conclusion: it suggests that STM may have a very short duration, unless it is rehearsed.
Bahrick (1975)
aim: research duration of LTM.
procedure: tested recall of people participants had gone to school with using photo recognition (50 photos from a person’s yearbook) and free recall (participants recalled all the names of their graduating class).
findings: found 90% accuracy for photo recognition for people who had graduated within 15 years and 60% and 30% for free recall.
conclusions: LTM lasts a very long time.
Multi Store Model of Memory
A representation of how memory works in terms of three stores called sensory register, STM and LTM. It describes how information is transferred from one store to another, how it is remembered and how it is forgotten.
Sensory Register
the memory stores for each of our five senses, such as vision (ionic store) and hearing (echoic store). Coding in the ionic sensory register it is acoustic. The capacity of the sensory register is huge and information lasts for a very short time - less than half a second.
STM
The limited capacity memory store. Coding is mainly acoustic, capacity is between 5 and 9 items on average, duration is between 18 and 30 seconds.
LTM
The permanent memory store. Coding is mainly semantic, it has unlimited capacity and can store memories for up to a lifetime.
