coding, capacity and duration Flashcards
what are the 2 types of memory
short term and long term
define STM
it is the limited capacity memory store
define LTM
it is the permanent memory store
define coding
the format in which information is stored in various memory stores
define capacity
the amount of information that can be held in memory stores
define duration
the length of time that information can be held in memory
what is the coding in STM
acoustically similar
what is the coding in LTM
semantically similar
what is the capacity in STM
5-9 items, limited
what is the capacity in LTM
unlimited capacity
what is the duration of STM
18 seconds
what is the duration of LTM
up to a lifetime
who did the research on coding
Baddeley
how did Baddeley research coding
he gave lists of types of words to 4 different groups to remember, they were given the original words and were then asked to recall them in the correct order immediately after as well as 20 minutes later to identify both STM and LTM
what were the 4 different groups of words
acoustically similar, acoustically dissimilar, semantically similar and semantically dissimilar
define acoustically similar
words that sound the same
define acoustically dissimilar
words that sound different
define semantically similar
words with similar meanings
define semantically dissimilar
words with different meanings
hpw did he identify which way STM and LTM is coded
but seeing generally which list of words was done worse in for the different times
what did his findings suggest
that stm is coded acoustically and ltm is coded semantically
who did the resarc on capacity
Jacobs 1887 and Miller 1956
what did Jacobs research
how much information the STM can hold in one time
how did Jacobs do his research
by measuring digit span
how did jacob measure digit span
the researcher would read out 4 digits and the participant is expected to recall them out loud in the correct order and then it continues until not all of the numbers or words have been recalled correctly and this tells us a persons individual digit span
what did jacobs research find
that the mean digit span across all participants was 9.3 and for letters it was 7.3
what did miller research
he made observations of everyday practice and studied the span of memory and chunking
how would he make these everyday observations
he would notice that most things come in 7, for eg 7 deadly sins, 7 days of the week ect and so he though the span of STM is about 7 items (plus or minus 2)
what else did miller notice that people could recall
he noticed that people could recall 5 words as easily as 5 letters
what is the method that miller observed that people do and what actually is it
Chunking- which is when you group sets of digits or letters into units or chunks
Who researched duration
Peterson x2 and Bahrick
What did Peterson x2 research
How short the duration of STM is
How did Peterson x2 do their study
On each trial students were given a consonant syllable to remember. Then a 3 digit number that they were told to count backwards from for a certain amount of times, each trial was different seconds. Then they were asked to recall the consonant syllable from the beginning
What was the purpose of counting backwards
To prevent any mental rehearsal
What are retention intervals
The different amount of seconds that they had to count backwards
What were Peterson x2 findings
After 3 seconds, average recall was about 80%, after 18 seconds it was about 3%. They suggested that STM duration may be about 18 seconds, unless there is verbal rehearsal
What did Bahrick study
The duration of LTM
How did Bahrick study the duration of LTM
He studied 392 American participants aged between 17 and 74 and the high-school yearbooks were obtained from the participants. Recall was tested by either photo recognition test of 50 photos or by free recall tests where participants recalled names od their graduating
What were the findings of Bahricks study
Participants tested within 15 years were about 90% accurate in photo recognition and after 48 years it declined to 70%. Free recall was less accurate, 60% after 15 years and then dropping to 30% after 48 years
What was Bahricks general finding
Shows that LTM may last up to a lifetime for some materials
What was a strength of Baddeley ls research
It identified a clear different between the 2 memory stores and the idea that STM uses acoustic coding and LTM uses semantic has stood out the test if time
What was a limitation of Baddeleys study
It used artificial stimuli rather than meaningful material which means his study may nkt tell us about coding in different kind of memory tasks especially in everyday life and this suggests that the findings from this study has limited application
What is a strength of Jacobs study
It has been replicated and confirmed and so this suggests that Jacobs study is a valid test of digit span in STM
What is a limitation of Millers research
He may have overestimated STM capacity as Cowan reviewed other research and concluded that the capacity of STM is only about 3-5 chunks and thus suggests that lower end of Millers estimate is more appropriate than 7 items
What is a limitation of Peterson x2
Is that the stimulus was artificial and recalling consonant syllable doesn’t reflect most everyday memory activities where what we try to remember is meaningful. This means that the study lacked external validity
What is a strength of Bahricks study
It has high external validity and this is because the researchers investigated meaningful memories. When studies on LTM were conducted with meaningless pictured to be remembered, recall rates were lower. Suggests his findings reflect a more real estimate of the duration of LTM
