Memory
Coding, Capacity & Duration of Memory
Research on coding:
Word recall of similar/dissimilar words
- Baddeley: acoustic in STM, semantic in LTM.
Evaluation:
Separate memory stores
- Identified STM and LTM, supporting multi-store models.
Artificial stimuli
- Word lists had no personal meaning.
Research on capacity:
Digit span
- Jacobs: 9.3 digits, 7.3 letters.
Span of memory and chunking
- Miller: 7±2 span, putting items together extends STM capacity.
Evaluation:
A valid study
- Later studies replicated findings (e.g. Bopp and Verhaeghen), so a valid test of digit span.
Not so many chunks
- Miller overestimated STM, only four chunks (Cowan).
Research on duration:
Duration of STM
- Peterson and Peterson: about 18 seconds without rehearsal.
Duration of LTM
- Bahrick et al. (yearbooks): face recognition 90%, free recall 60% (15 years). Face recognition
70%, free recall 30% (48 years).
Evaluation:
Meaningless stimuli in STM study
- Peterson used consonant syllables, lacking external validity.
High external validity
- Bahrick et al. used meaningful materials, better recall than studies with meaningless stimuli
(Shepard).
Coding, Capacity & Duration of Memory
Research on coding:
Word recall of similar/dissimilar words
- Baddeley: acoustic in STM, semantic in LTM.
Evaluation:
Separate memory stores
- Identified STM and LTM, supporting multi-store models.
Artificial stimuli
- Word lists had no personal meaning.
Research on capacity:
Digit span
- Jacobs: 9.3 digits, 7.3 letters.
Span of memory and chunking
- Miller: 7±2 span, putting items together extends STM capacity.
Evaluation:
A valid study
- Later studies replicated findings (e.g. Bopp and Verhaeghen), so a valid test of digit span.
Not so many chunks
- Miller overestimated STM, only four chunks (Cowan).
Research on duration:
Duration of STM
- Peterson and Peterson: about 18 seconds without rehearsal.
Duration of LTM
- Bahrick et al. (yearbooks): face recognition 90%, free recall 60% (15 years). Face recognition
70%, free recall 30% (48 years).
Evaluation:
Meaningless stimuli in STM study
- Peterson used consonant syllables, lacking external validity.
High external validity
- Bahrick et al. used meaningful materials, better recall than studies with meaningless stimuli
(Shepard).
