Memory - Introduction to Memory Flashcards
Procedure Baddeley (1966) Coding in STM and LTM
Acoustically similar words (e.g. cat, cab) or dissimilar (e.g. pit, few).
Semantically similar words (e.g. large, big) or dissimilar (e.g. good, hot).
Findings and Conclusions
Baddeley (1966) Coding in STM and LTM
Immediate recall worse with acoustically similar words, STM is acoustic.
Recall after 20 minutes worse with semantically similar words, LTM is semantic.
Procedure
Jacobs (1887) Capacity of STM
Digit span: Researcher reads four digits and increases until the participant cannot recall the order correctly.
Findings and Conclusions
Jacobs (1887) Capacity of STM
On average, participants could repeat back 9.3 numbers and 7.3 letters in the correct order immediately after they were presented.
Procedure
Miller (1956) Capacity of STM
Miller made observations of everyday practice. For example, he noted that things come in sevens: there are 7 notes on the musical scale, 7 days of the week, 7 deadly sins, and so on.
Findings and Conclusions
Miller (1956) Capacity of STM
The span of STM is about 7 items (plus or minus 2) but can be improved by chunking - grouping sets of digits/letters into meaningful units.
Procedure
Peterson and Peterson (1959) Duration of STM
24 students were given a consonant syllable (e.g. YCG) to remember and a 3-digit number to count backwards for 3, 6, 9 12, 15 or 18 seconds.
Findings and Conclusions
Peterson and Peterson (1959) Duration of STM
Students recalled (on average) about 80% of the syllables correctly with a 3-second interval. Average recall after 18 seconds fell to about 3%. Suggesting that duration of STM without rehearsal is about 18 to 30 seconds.
Procedure
Bahrick et al. (1975) Duration of LTM
Participants were 392 Americans aged between 17 and 74.
- Recognition test: 50 photos from participants’ high school yearbook.
- Free recall test: Participants listed names of their graduating class.
Findings and Conclusions
Bahrick et al. (1975) Duration of LTM
Participants tested 48 years after graduation were about 70% accurate in photo recognition. Free recall was less accurate.
What are the strengths of research into coding, capacity and duration of memory?
- Bahrick et al.’s study has high external validity
What are the weaknesses of research into coding, capacity and duration of memory?
- Baddeley’s study didn’t use meaningful material
- Jacob’s study was conducted a long time ago
- Miller’s research may have overestimated the capacity of STM
- Peterson and Peterson’s study had artificial stimulus
How does Bahrick et al.’s study have high external validity?
Real-life meaningful memories (e.g. of people’s faces and names) were studied.
When lab studies were done with meaningless pictures to be remembered, recall rates were lower (e.g. Shepard 1967).
The downside of such real-life research is that confounding variables are not controlled, such as the fact that Bahrick’s participants may have looked at their yearbook photos and rehearsed their memories over the years.
Why is Baddeley’s study not using meaningful material a weakness?
The words used in the study had no personal meaning to the participants.
When processing more meaningful information, people may use semantic coding even for STM tasks.
This means the results of this study have limited application. We should be cautious about generalising the findings to different kinds of memory task.
Why is Jacob’s study being conducted a long time ago a weakness?
Early research in psychology often lacked adequate control of extraneous variables.
For example, some participants may have been distracted while they were being tested so they didn’t perform as well as they might.
This would mean that the results may not be valid because there were confounding variables that were not controlled.
However, these results have been confirmed in other research, supporting its validity.
How did Miller’s research overestimate the capacity of STM?
For example, Cowan (2001) reviewed other research. He concluded that the capacity of STM was only about 4 chunks.
This suggests that the lower end of Miller’s estimate (5 items) is more appropriate than 7 items.
How does Peterson and Peterson’s study use artificial stimulus?
Trying to memorise consonant syllables does not reflect most real-life memory activities where what we try to remember is meaningful.
So it could be argued that this study lacked external validity.
On the other hand, we do sometimes try to remember fairly meaningless things, such as phone numbers. So the study is not totally irrelevant.
Who was Patient KF?
- KF was in a motorcycle accident, resulting in brain damage to his left occipital lobe
- STM was damaged but LTM was normal (supports MSM)
- he remembers words better if presented visually as opposed to auditorily (supports WMM)
