Lesson 1 - Capacity, Duration and Coding of memory Flashcards
1
Q
Peterson and Peterson (1959)
A
- investigated the duration of the short term memory
- used 24 undergraduates
- they were shown a consonant trigram (eg. ZHT)
- They were then asked to count backwards in threes to ensure that they were focused on counting and not rehearsing the trigram
- after intervals of 3, 6, 9, 12, 15 or 18 seconds they were asked to stop and repeat the trigram
- 90% was remembered after 3 seconds, 20% after 9 seconds and less than 10% after 18 seconds.
2
Q
Strengths of Peterson and Peterson (1959)
A
- It was a lab experiment where the variables could be closely controlled
- it is a repeatable experiment and can be done over different time periods to investigate changes in memory over time.
3
Q
Weaknesses of Peterson and Peterson (1959)
A
- it has low ecological validity (cannot apply to real life) because we don’t have the need to recall nonsense trigrams in everyday life
- there may have been interference, as the trigrams from previous trials may have confused the participants, and they might not have necessarily forgotten
4
Q
Research support for STM duration
A
Peterson and Peterson (1959)
5
Q
Research support for LTM duration
A
Bahrick et al (1975)
6
Q
Bahrick et al (1975)
A
- investigated the duration of the long-term memory
- tested 400 Americans (17-74)
- they were asked to recall their former classmates from picture cues, matching names to faces and remembering names with no cues at all.
- after many years in some cases, accuracy was at 70% (with cues) and 30% (without cues)
7
Q
Duration of the short term memory
A
Up to 30 seconds without rehearsal
8
Q
Strengths of Bahrick et al (1975)
A
- Has high external validity, as remembering old classmates is meaningful information. This gives us a better idea of the LTM duration.
9
Q
Weaknesses of Bahrick et al (1975)
A
- The participants may have been in touch with their former classmates. As this is a natural experiment, the investigators could not do much about this. This is a confounding variable.
- The information recalled (names of old classmates) are meaningful, therefore it may have been rehearsed, therefore it cannot be applied to all long-term memories.
10
Q
Duration of the long term memory
A
Possibly a lifetime
11
Q
Jacobs (1887)
A
- investigated the capacity of the short term memory
- Developed the digit span technique
- 4 digits/letters were read out to participants and they were asked to repeat it back. A digit/letter was added on each time until the whole string could not be repeated back correctly.
- On average, 9 digits and 7 letters were remembered – supports Miller (1956).
- The capacity increased with age, as the average capacity for an 8 year old was 6. Could be due to increase in brain capacity or learning strategies to improve brain capacity, like chunking.
- Digits may have been easier to recall as there are only 10 digits, but 26 letters
12
Q
Weaknesses of Jacobs (1887)
A
- Lacks ecological validity, as remembering random letters and numbers is not a common everyday activity and cannot be applied to real life.
- There could have been interference with previous digit strings. Could be a confounding variable.
- Due to the fact it was conducted so long ago, we cannot be sure that all variables are properly controlled. However it has been repeated and the same results were found.
13
Q
Miller (1956)
A
- thought that the capacity of the short term memory was 5-9 items (7±2)
- He also thought that 5 words could be remembered as well as 5 letters through ‘chunking’.
14
Q
Capacity of the short term memory
A
5-9 items
15
Q
Capacity of the long term memory
A
Potentially unlimited
