2. Memory Flashcards
What is short-term memory?
The limited capacity memory store
What is long-term memory?
The permanent memory store
What is the coding, capacity and duration of the STM?
- Coding = acoustic
- Capacity = 5-9 items
- Duration = 18 seconds
What is the coding, capacity and duration of the LTM?
- Coding = semantic
- Capacity = unlimited
- Duration = up to a lifetime
What is coding?
The format in which information is stored in the various memory stores
What is capacity?
The amount of information that can be held in a memory store
What is duration?
The length of time information can be held in memory
Describe Baddeley’s research on coding and its findings
- Gave different lists of words to 4 groups to remember
- Group 1: acoustically similar
- Group 2: acoustically dissimilar
- Group 3: semantically similar
- Group 4: semantically dissimilar
- Participants shown original words and asked to recall in correct order
- When done immediately, they did worse on acoustically similar
- When recalled after 20 minute interval, they did worse with semantically similar
- Information coded acoustically in STM, semantically in LTM
Describe Jacobs research on capacity (digit span)
- Researcher reads out 4 digits and participant recalls out loud in correct order
- If correct, researcher reads out 5 digits and so on
- Continues until participant cannot recall order correctly
- Indicates the individuals digit span
- Mean span for digits across all participants was 9.3 items
- Mean span for letters 7.3
Describe Millers research on capacity (Span of memory and chunking)
- Made observations of everyday practice
- Stated that the span of STM is about 7 items, plus or minus 2
- Also noted that people can recall 5 words as easily as 5 letters, through chunking (grouping sets of digits/letters into units or chunks)
Describe Peterson and Peterson’s study on the duration of STM
- Tested 24 children in 8 trials each
- In each trial they were given a consonant syllable to remember, also given a 3-digit number
- Student counted backwards to prevent mental rehearsal
- On each trial they were told to stop after varying periods of time (3, 6 9, 12, 15 or 18 seconds)
- After 3 seconds, average recall was 80%, after 18 seconds it was about 3%
- Findings suggest STM duration may be about 18 seconds
Describe Bahrick et al’s study on the duration of LTM
- Studied 392 American participants aged 17-74
- Tested recall in various ways
- Photo recognition test: consisting of 50 photos from participants high school yearbooks
- Free recall test: participants recalled all the names of their graduating class
- Photo recognition: participants tested within 15 years of graduation were 90%, after 48 years, recall declined to 70%
- Free recall: those tested after 15 years were 60% accurate, dropped to 30% after 48 years
AO3 for research on coding
1. Separate memory stores: Baddeley identified clear difference between stores, ideas of coding in STM and LTM were proved by research, important steep in our understanding of the memory, which led to multi-store memory
2. Artificial stimuli: Baddeley’s word lists had no personal meaning to participants, so findings don’t tell us much about coding in different memory tasks especially everyday life, when processing more meaningful information people may use semantic coding even for STM, findings have limited application
AO3 for research on capacity
1. A valid study: study has been replicated, the study is very old and early research often lacked controls, some participants digit spans may have been underestimated as they were distracted during testing, however Jacobs findings have been confirmed by other, better controlled studies since
2. Not so many chunks: STM capacity may be overestimated, Cowan (2001) reviewed other research and concluded that STM capacity is only about 4(plus or minus 1) chunks, suggests that lower end of Millers estimate (five items) is more appropriate than 7 items
AO3 for research on duration of STM and LTM
1. Meaningless stimuli in STM study: in Peterson and Peterson’s study material was artificial, recalling consonant syllables does not reflect most everyday memory where what we are trying to remember is meaningful, lacks external validity, however not completely irrelevant as sometimes people try to remember meaningless stimuli e.g phone numbers
2. High external validity: in Bahrick’s study researchers investigated meaningful memories e.g peoples names and faces, when studies on LTM conducted with meaningless pictures to be remembered recall rates were lower, Bahrick’s studies reflect a more ‘real’ estimate of duration
