Memory Flashcards
What is short term memory?
Short term memory stores and allows recall of information for a period of several seconds.
What is long term memory?
Stores and enables us to recall information from the more distant past.
In which 3 ways are STM and LTM different?
Duration, capacity and encoding
What is duration?
A measure of how long information can be stored for or how long it lasts.
Who investigated the duration of STM?
Peterson and Peterson.
- 24 undergraduate students were presented with a consonant trigram.
- They were then asked to count backwards in threes to stop them repeating/rehearsing the consonant trigram.
- After intervals of either 3, 6 ,9, 12, 15 or 18 seconds, participants had to stop counting and repeat the trigram.
What were the results of Peterson and Peterson’s study?
- Participants could remember about 80% of trigrams after 3 seconds.
- 20% after 9 seconds
- Less than 10% when there was a 18 second interval.
- The maximum STM duration is about 18-30 seconds.
Evaluate Peterson and Peterson’s study on the duration of STM.
Strengths
1) It is a lab experiment where variables can be tightly controlled e.g how many trigrams are presented. The procedure can also be replicated to test if results are reliable.
Weaknesses
1) Trigrams are unrealistic things to remember. Therefore it has low ecological validity.
2) Trigrams presented on earlier trials may have cause confusion when participants came to remember trigrams in later trials.
Who investigated the duration of LTM?
Bahrick et al.
- Tested how well about 400 American participants could remember their former classmates by asking them to identify pictures, matching names to pictures.
What were the results of Bahrick’s study?
- Even after 48 years, when asked to link names and faces, accuracy was at about 70%.
- However, when participants were asked to free recall to names of their classmates, accuracy was about 30%
- This backs up the idea that long term memories can last a lifetime.
Evaluate Bahrick et al’s study.
Strengths
- This was a natural experiment with meaningful material so has higher ecological validity because remembering names is an everyday task.
Weaknesses
- It only looked at a specific type of information (names of classmates). This type of information is particularly meaningful and regularly rehearsed. Not all LTM’s remain there for a lifetime.
- Because it is a natural experiment, the experimenter had less control of the IV thus it’s likely some of the names had been rehearsed e.g if classmates were still in touch. This would be a confounding variable, making results potentially invalid.
What is capacity?
A measure of how much information can be held or stored.
How did Jacobs investigate the capacity of the STM?
- Jacobs developed a serial span technique.
- The researcher read out 4 digits and the participant was asked to repeat it back.
- Another digit was added until the participant could not repeat back the digit string accurately.
What were the results of Jacobs study?
- On average about 9 digits and 7 letters were correctly recalled.
- This capacity increased with age.
- This may be because there is a gradual increase in brain capacity, and/or because people develop strategies to improve their digit span, such as chunking.
- Digits may have been easier to recall as there are only 10 digits to remember, compared to 26 letters.
Evaluate Jacob’s study.
- Jacob’s research lacks ecological validity- learning random lists of numbers is not a realistic test of STM.
- Given Jacob’s study was conducted so long ago we also cannot be sure that extraneous variables were controlled.
What did Miller conclude?
- He concluded that the STM has a capacity of 7+-2 items.
- He also said that memory capacity can be increased through a process called chunking.
Which 3 possible ways can information be coded?
- Acoustic coding: storing information in terms of the way it sounds.
- Semantic coding: coding information in terms of its meaning.
- Visual coding: storing information in terms of the way it looks.
How did Baddely investigate coding?
- Participants were shown a sequence of 5 words under one of the four conditions, and then immediately had to write them down in order.
- Acoustically similar, acoustically dissimilar, semantically similar, semantically dissimilar
What were the results of Baddely’s experiment?
- When tested immediately, participants were least accurate with the acoustically similar words- they commonly got them muddled.
- When tested 20 minutes later, participants were least accurate with semantically-similar words.
- In conclusion, information is normally coded acoustically in the STM and semantically in the LTM.
Evaluate Baddely’s experiment.
- Low ecologically validity- the words were a meaningless list, and perhaps semantic coding is only used when information is more meaningful.
- This means that the results have limited application to real life.
Who first introduced the multi-store model?
Atkinson and Shiffrin in 1968
What are the 3 unitary stores of the multi-store model?
1) Sensory register or sensory memory
2) Short term memory
3) Long term memory
What does the multi-store model work?
1) Information is detected by the sense organs and enters the sensory memory.
2) If attended to this, information enters the STM.
3) Information from the STM is transferred to the LTM only if that information is rehearsed.
4) If rehearsal does not occur, then information is forgotten, lost from STM through the processes of displacement or decay.
What are the 5 separate sensory stores?
1) Iconic store- Where visual images are kept for a short period.
2) Echoic store- Where auditory senses are kept for a short period.
3) Haptic store- Retains physical senses of touch and internal muscle tensions.
4) Gustatory store: Related to taste information
5) Olfactory store: Related to smell
What is the duration of the sensory register?
Less than half a second (250 milliseconds)