TOPIC: MEMORY Flashcards
(41 cards)
What is the capasity of sensory register?
Unknown
What is the capasity of LTM?
Unlimited
What is the capacity of STM?
5-9 items
What is the duration of sensory register?
1/2 a second
stores sensory information
What is the duration of STM?
stores information for 18 seconds
What is the duration of LTM?
Unlimited
How is sensory register coded?
Through the senses
How is STM coded ?
Acoustically
How is LTM coded?
Semantically
Capacity - STM
RESEARCHER: JACOBS’
What is his research and what did he find?
Capacity = 5 - 9 items
Jacobs (1887) : Supports Miller’s psychological theory
- Used the digit span technique to asses the capacity of STM
- Used a sample of 443 female students ( aged from 8-19 )
- Participants had to repeat back a string of numbers or letters in the same order and the number of digits/ letters was gradually increased until the ppts could no longer recall the sequences.
HE FOUND:
Average span for digits - 9.3 items ] Suppots Miller’s notion of 7+/-2
Average span for letters - 7.3 items ]
- Jacobs suggest that digits are easier to rememvber because there are only 9 in total, compared to 26 letters in the alphabet.
Capacity - STM
RESEARCHER : MILLERS’
What did he do in his experiment?
Miller suggested:
*Span of STM is 7 items ( includes letters, musical notes and words )
OR
*Span varies from 5-9 items
*You can recall 5 words just as well as 5 words because we tend to chunk things together so that we can remember more rather than individual numbers or letters.
~ These studies show us that the capacity of STM is fairly limited, however “chunking” information can help
RESEARCHER : MILLER [ EVALUATION ]
- Questions internal validity
- His is supported by a psychologist (Jacobs), yet he did not specify how large each ‘chunk’ of information could be and therefore we are unable to conclude the exact capacity of STM.
- Consequently, further research is needed to find the exact capcity of STM to determine each size of information ‘chunked’
- Did not consider other factors of STM
e.g. age - yet Jacobs (1887) research acknowledged that STM is gradually improved with age - These studies show us that the capacity of STM is fairly limited, however ‘chunking’ information can help
Miller’s (1956) theory is supported by psychological research. For example, Jacobs (1887) conducted an experiment using a digit span test, to examine the capacity of short-term memory for numbers and letters. Jacobs used a sample of 443 female students (aged from 8-19) from the North London Collegiate School. Participants had to repeat back a string of numbers or letters in the same order and the number of digits/letters was gradually increased, until the participants could no longer recall the sequence. Jacobs found that the student had an average span of 7.3 letters and 9.3 words, which supports Miller’s notion of 7+/-2. (POSITIVES)
Cowan argues that this type of task sets the participant up to employ “processing strategies” that do not reflect how we actually use our short-term memory on a day to day basis. - low ecological validity ( NEGATIVE )
Although Miller’s (1956) theory is supported by psychological research, he did not specify how large each ‘chunk’ of information could be and therefore we are unable to conclude the exact capacity of short-term memory. Consequently, further research is required to determine the size of information ‘chunks’ to understand the exact capacity of short-term memory. ( NEGATIVE )
Finally, Miller’s (1956) research into short-term memory did not take into account other factors that affect capacity. For example, age could also affect short-term memory and Jacobs (1887) research acknowledged that short-term memory gradually improved with age. ( NEGATIVE )
RESEARCHER: PETERSON & PETERSON
DURATION - STM
- 24 students took part in the experiment
- Had to recall meaningless three-letter trigrams ( e.g. FHD, BHC ) at different intervals
- To prevent rehearsal ~ had to count backwards in threes or fours from a specific number, until they were asked to recall the letters.
RESULTS:
- Longer the interval the less accurate the recall
- At 3 seconds, 90% of the trigrams were correctly recalled, whereas at 18 seconds only 10% were correctly recalled.
- P&P concluded that STM had a limited duration of 18 seconds
- The results show that if we are unable to rehearse information, it will not be passed to long-term memory.
RESEARCHER: PETERSON & PETERSON [ EVALUATION ]
- P&P had used 24 psychology students - may have had previous knowledge about the multi- store model of memory … may have demonstarted demand characteristcs, changed their behaviour to asssit the experiment.
- The results lacks generalisablity, so cannot apply to the rest of the people
- Low levels of ecological validity, unable to apply these results to everyday examples, unable to conclude if the duration of short-term memory may be longer for more important information
HOWERVER:
- HIghly controlled
- High degree of control for extraneous variables, which makes it easier to replicate their procedure.
CODING
BADDLEY (1966)
-Gave participants list of words to remember
- Acou. similar
- Acou. disimilar
- Sema. similar
- Sema. dissimilar
- when asked to recall the words immediately (STM), or 20 minutes later (LTM) participants had difficulty remembering the accoustically similar words in STM but not in LTM
- Whereas semantically similar words were difficult to remember in LTM but not in STM
RESEARCHER: MURDOCK
What was his experiment?
YEAR IT WAS PUBLISHED : 1962
AIM: How many words a person can remember at a given time
- Total of 103 participants
- METHOD/ PROCEDURE: PPts were presented with a list of 10 to 40 words, one word at time , at a rate of either one word per second or one word every two seconds
- RESULTS: Found out that the probability of recalling any word depended on its serial position in the list
Moreover words presented at the beginning and end were more recalled than the words in the middle
- CONCLUSION: The thing you need to remember about the memory stores is that the STM has a limited capacity and duration, and information can pass through to the LTM store depending on elaborate rehearsal processes. The middle words in the list are likely forgotten because they were not elaborately rehearsed and so could not move to LTM and were displaced from the STM by later words in the list due to the store’s limited capacity.
RESEARCHER: MURDOCK ( EVALUATION )
+ The study used a standardised procedure so the research could be easily replicated and assessed to measure its reliability. In addition, it ensures the study has high internal reliability as the same procedure was used for each participant.
+ The study was conducted in a lab setting. In lab studies, researchers have a high level of control and can prevent extraneous variables from affecting the study’s validity.
- The study recruited a non-representative sample. The study recruited psychology students, so they may have been able to guess the study’s aims and act accordingly to the Hawthorne effect. Moreover, as the study used a small sample, it isn’t easy to generalise the findings to the population.
- The study can be reductionist, as it over-simplifies memory by measuring the ability based on the accuracy of recalling a list of words. Different results may be found if we measure different types of memories, names or words with associations.
What is coding?
can be stored acoustically or visually ( LTM, Semantic )
What is capacity?
How much?
What is duration?
How long?
CODING
STM AND LTM
when words around too similar the STM has difficulty distinguishing between these sounds - it prefers words that sounds different to one another, which supportsthe claim that STM use acoustic encoding
when words have a similar meaning the LTM has difficulty differentiating between them and so gets confused»_space; this is why the LTM prefers to encode information semantically giving each word a different meaning
How does sensory register code?
through the senses
how does short term memory code?
acoustically
how does long term memory code?
semantically ( sometime visually, sometime acoustically )
