Coding,Capacity & Duration Flashcards
What is cognitive psychology?
The study of mental processes e.g memory,thinking,problem solving etc.
Define ‘memory’
Information/experiences/procedural memory (riding a bike etc) that is stored to be recalled upon at a later date.
Define coding
The way information is taken into memory
What are the types of encoding?
Visual (as an image)
Acoustic (sound)
Semantic (through meaning)
Define capacity
The amount of information a memory store can hold
Define duration
How long the memory lasts in that store
How is coding in STM done?
Coding in STM is done by sound (acoustically)
Therefore words that sound alike are muddled up and it is more likely that you will not remember them so well when tested immediately
e.g. cab,fab,dad,fad,crab
How is coding in your LTM done?
Done semantically (by meaning)
Therefore words that have similar meaning are muddled up and it is more likely that you will not remember them so well when tested immediately
e.g. big, giant, enormous,tall
What was the research conducted on coding?
Alan Baddeley gave different lists of words to 4 groups of ppts to remember
Group 1 (acoustically similar): words sounded similar e.g. cat,cab,can
Group 2 (acoustically dissimilar): words sounded different e.g. pit,few,cow
Group 3 (semantically similar): words with similar meanings e.g. great,large,big
Group 4 (semantically disimilar): words with different meanings e.g. good,huge,hot
Ppts were shown the original words & asked to recall them in the correct order
What were Baddeley’s findings?
- When they did this task immediately, recalling from STM they tended to do worse with acoustically similar words
- When they recalled the word list after 20 mins, recalling from their LTM they did worse with semantically similar words
- Findings suggest that information is coded acoustically in STM & semantically in LTM
What is one strength of Baddeley’s study?
It identified a clear difference between the two memory stores
Later research showed there were some exeptions to his findings but the idea that STM mostly codes acoustically & LTM mostly codes semantically has stood the test of time
What was one limitation of Baddeleys study?
It used quite artificial stimuli rather than meaningful material
e.g. the word lists had no meaning to the ppts
So B’s findings may not tell us about coding in different types of memory tasks, especially in everyday life
When processing more meaninigful info people may use semantic coding even for STM tasks
Suggests that the findings from this study have limited application
What research was conducted on capacity of STM?
Jacobs (1887) used digit span to measure capacity
Procedure:
The researcher reads out 4 digits & the ppts recalls these outloud in the correct order
If this is correct researcher will read out 5 digits & so on till ppt cannot recall the order correctly- this indicates the individuals digit span
What were Jacobs findings of capacity of STM?
Found that the mean span for digits across all ppts was 9.3 items
The mean span for letters was 7.3
What is one strength of Jacob’s (1887) study?
Is that it has been replicated
Study is very old & early research can often lack adequate controls
e.g. some ppts may have been underestimated because they were distracted during testing
Suggests Jacob’s study is a valid test of digit span in STM
What did George Miller notice amongst the capacity of STM?
He made observations of everyday practice e.g. noticed that things tend to come in 7’s: 7 notes on music scale, 7 days of the week etc.
Miller thought that span i.e capacity of STM is about 7 items plus or minus 2
But he also noted that people can recall 5 words as easily as they can recall 5 letters. Do this by chunking
How do you measure the capacity of LTM?
Not possible
We could say its limitless
What is one limitation of Miller’s research?
He may have overestimated STM capacity
Cowman (2001) reviewed other research & concluded that capacit of STM is only about 4(+/-) 1
Suggests that the lower end of Millers estimate (5) items is more appropriate than 7 items
What research was conducted on the Duration of STM?
Peterson & Peterson
Tested 24 students in 8 trials each
On each trial the student was given a consonant syllable (such as YCG) to remember.
They were also given a 3 digit number. The student counted backwards from this number until told to stop
The counting backwards was to prevent any mental rehearsal of the consonant syllable (increasing the duration of STM for the syllable
On each trial they were told to stop after varying periods of time: 3,6,9,12,15 or 18 seconds
What were Peterson & Peterson’s findings?
After 3 secs average recall was around 80%
After 18 seconds it was about 3%
Peterson & Peterson’s findings suggested that STM duration may be about 18 seconds unless we repeat info over & over
What was one limitation of Peterson & Peterson’s study?
The stimulus material was artificial
Study was not completely irrelevant as we do sometimes try to remember farily meaningless material (e.g. phone numbers)
Recalling consonant syllables does not reflect most everyday memory
We usually try to remeber meaningful things
Means study lacked external validity
What is the counterpoint for Peterson & Peterson’s evaluation?
Nowadays we use abreviations & consonant syllables a lot more often due to social media
Meaning that the external validitiy would be higher nowadays than it was in 1959
What research was conducted on the duration of LTM?
Harry Bahrick et al (1975)
Studied 392 American ppts aged between 17 & 74
High school yearbooks were obtained from the ppts or directly from some schools
Recall tested in various ways including:
1. Photo recognition test consisting of 50 photos from yr book
2. Free recall test where ppts recalled all the names of their graduating class
What were Bahricks findings?
Ppts tested within 15 years of graduation were about 90% accurate in photo recognition
After 48 years recall declined to 70% for photo recognition
FREE RECALL LESS ACCURATE THAN RECOGNITION
free recall declined to 60% after 15 years
dropping to 30% after 48 years
This shows that LTM may last forup to a life time for some material
What a strength of Bahrick’s study?
Has high external validity
Becuase the researchers investigated meaningful memories (peoles names & faces)
When other studies on LTM were conducted with meaingless pics to be remebered recall rates were lower
Suggests Bahrick’s findings reflect a more ‘real’ estimate of the duration of LTM
