Memory L1 - 4 Flashcards
Duration:
Measure of how long info can be stored for
To keep info in STM for more than a few secs, what do humans do?
Rehearse the info
Which study supports the duration of STM?
Peterson and Peterson (1959)
Procedure of Peterson and Peterson (1959) study:
1) 24 undergrads presented w/ consonant trigram
2) Asked to count backwards in threes from random digit number to prevent rehearsal of trigram
3) After intervals of 3, 6, 9, 12, 15, 18 secs, participants had to repeat trigram
Results of Peterson and Peterson (1959) study:
- After 3 secs, 90% of trigrams could be remembered
- After 9 secs, 20%
- After 18 secs, less than 10%
Conclusion of Peterson and Peterson (1959) study:
- Info decays quickly when it can’t be rehearsed
- Max STM duration is 18-30 secs w/out rehearsal
Strengths and weaknesses of Peterson and Peterson (1959) study:
+ Variables are tightly controlled so study can be replicated
- Low ecological validity as trigrams are unrealistic (lacks mundane realism)
- Lacks pop validity (only undergrads)
- Was forgetting due to confusion from trigrams presented earlier (interference) or actual forgetting?
Which study supports the duration of LTM?
Bahrick et al (1975)
Procedure of Bahrick et al (1975) study:
Tested how well American pps between ages 17 and 74 could remember former classmates by identifying pics, matching names to pics and recalling names w/ no pic cue
Results of Bahrick et al (1975) study:
Even after 48 yrs:
- Linking names to pics –> 70% accuracy
- Free recall –> 30% accuracy
Conclusion of Bahrick et al (1975) study:
- Long term memory can last a lifetime
- Individuals cannot access LTM memories immediately, but recall is much higher when presented w/ cues
Strengths and weaknesses of Bahrick et al (1975) study:
+ High external validity as meaningful material was investigated
- Less control of IV as it is a natural experiment so there is a possibility names may have been rehearsed (confounding variable)
- Looks at very specific type of info (meaningful + regularly rehearsed)
In conclusion, what is the duration of STM and LTM?
Duration of STM: 18-30 secs
Duration of LTM: Lifetime
Which study supports the capacity of STM?
Jacobs (1887)
Procedure of Jacobs (1887) study:
Developed digit span technique
1) Researcher read out 4 digits and asked to repeat it back immediately
2) More digits added until pp could not repeat it accurately
Results of Jacobs (1887) study and reasoning:
- On average, 9 digits and 7 letters recalled
- Capacity increased with age during childhood (avg digit span for 8 yr olds was 6) due to gradual increase in brain capacity/strategies developed eg. chunking
- Digits may be easier to recall because there are only 10 to remember compared to 26 letters in alphabet
Strengths and weaknesses of Jacobs (1887) study:
+ Has been repeated since w/ same results so it is valid
- Lacks ecological validity as repeating random lists of numbers is not realistic as more meaningful info may be recalled better
-Previous sequences recalled may have confused the pp
-Cannot be sure whether EVs were controlled as it was conducted long ago (lacks temporal validity)
Which study reviewed the capacity of STM and what did it conclude?
- Miller (1956)
- Capacity of 7±2 items
- Memory capacity can be increased through chunking eg. Ppl can remember 5 letters as well as 5 words
What is one evaluation of Miller’s (1956) study?
- Size of chunk matters
- Cowan (2001) reviewed research and argued Miller may have overestimated the capacity of STM
- Concluded capacity was about 4 chunks
Coding:
Form in which info can be stored in the various memories
What are the 3 ways of coding?
- Acoustic –> storing info in terms of way it sounds
- Semantic –> coding info in terms of meaning
- Visual –> storing info in terms of the way it looks
Which study supports the coding of STM and LTM?
Baddeley (1966)
Procedure of Baddeley (1966) study:
Participant shown sequence of 5 words under these 4 conditions + immediately/after 20 mins write them down in order
1) Acoustically similar
2) Acoustically dissimilar
3) Semantically similar
4) Semantically dissimilar
Results of Baddeley (1966) study:
- Tested immediately –> least accurate w/ acoustically similar words
- Tested after 20 mins –> least accurate w/ semantically similar words
Conclusion of Baddeley (1966) study:
- Info is normally encoded acoustically in STM
- Info is normally encoded semantically in LTM
- Info can also be stored in other forms eg. visual
Strengths and weaknesses of Baddeley (1966) study:
+ Identifies clear difference in coding of two memory stores
- Low ecological validity as list was meaningless (lack of mundane realism)
Who proposed the multi-store model, what does it argue and how can it be described?
- Atkinson and Shiffrin (1968)
- Memory involves flow of info through a series of stages in a fixed linear sequence
- Described as an information processing model (w/input, process and output)
What are the 3 unitary stores of the model?
1) Sensory register
2) STM
3) LTM
Explain MSM:
1) Info is detected by sense organs and enters sensory register
2) If attention is paid, info enters STM, which can be recalled directly. If not, info is lost through displacement
3) If prolonged rehearsal occurs (maintenance proposed by Atkinson + Shiffrin, elaborative proposed by Raaijmakers + Shiffrin (2003)), info enters LTM. Up until this point there is a rehearsal loop w/in STM.
4) Info must be transferred back into STM to be retrieved from LTM
Maintenance rehearsal:
Mental repetition of material
Elaborative rehearsal:
- Material is given some kind of meaning
- More advanced type of rehearsal
Describe the coding for the sensory register
Modality specific. It can be:
- Haptic (touch)
- Ionic (visual)
- Echoic (auditory)
- Gustatory (taste)
- Olfactory (smell)
What does the sensory register do?
Stores sensory info from environment in a short period of time
Describe the capacity and duration of sensory register
Duration: 250 ms
Capacity: Unlimited
Which study supports the sensory register?
Sperling (1960)