Memory - STM & LTM Flashcards
What is memory?
The process by which we retain and recall information about events that happened in the past
What is short term memory?
Your memory for immediate events, disappears if not rehearsed
What is long term memory?
Your memory for events that have happened in the past, from anywhere between 2 minutes and 100 years ago
What is the capacity for STM? Who reached this discovery?
LIMITED
Jacobs et al found that 5-9 items can be stored in the STM and that digits (9) are easier to remember than letters (7)
Who proposed the technique chunking ?
Miller found that CHUNKING can increase the number of items retained in the STM
What was Jacob et al’s (1887) procedure?
Participants were asked to recall digits and then letters after seeing them
What are the weaknesses of Jacob et al’s study?
Confounding variables weren’t controlled in the investigation so LACKS VALIDITY
For example: Some participants might have been distracted so they didn’t perform well
LACKS ECOLOGICAL VALIDITY , recalling lists of letters have little relevance to everyday activities
What did Miller not take into account?
The participant’s age
What is the duration of the STM?
Duration is limited to a maximum of 30 seconds which can be extended through rehearsal (if done long enough will result in transfer of the info into LTM where it will become long lasting)
What were Jacob et al’s findings?
The mean span for remembered digits was 9.3
The mean span for letters was 7.3
Who researched the duration of STM? What was their procedure?
Peterson and Peterson (1959)
Read nonsense trigrams to participants, and then got them to count backwards in threes from a large three-digit number (to prevent repetition of the letters)
What was Peterson and Peterson’s findings?
They found that 90% of trigrams were recalled correctly after 3 seconds, but only 5% after 18 seconds
Suggests that STM duration has a capacity between 20 and 30 seconds
What are the weaknesses of Peterson and Peterson’s investigation?
The results may be flawed by methodology because different trigrams were used on each trial, this may have led to interference between items, leading to decreased recall
LACKS ECOLOGICAL VALIDITY because nonsense trigrams have little relevance to STM tasks in everyday life
How is information coded in the STM?
Acoustically
Who investigated coding in STM and LTM? What was their aim?
Professor Alan Baddeley aimed to assess whether coding in the STM and LTM is mainly acoustic (by sound) or semantically (by meaning)
What was Baddeley’s procedure?
75 participants were presented with one of four word lists repeated four times.
List A - acoustically similar (cat, mat, bat)
List B - acoustically dissimilar (pit, cow, day)
List C - semantically similar (big, huge, tall)
List D - semantically dissimilar (hot, safe, foul)
How did Baddeley test coding in STM?
Participants were given a list containing the original words in the wrong order. Their task was to rearrange the words in the correct order
How did Baddeley test coding in the LTM?
The procedure for LTM was the same as for the STM, but with a 20-minute interval before recall, during which the participant performed another task to prevent rehearsal .
What did Baddeley find out about LTM coding based on his results?
For LTM, participants with List C (semantically similar) performed the worst, with a recall of only 55% . They confused similar -meaning words e.g recalling ‘big’ instead of ‘huge’. Suggesting that LTM is coded semantically
Recall of the other lists was comparatively good at between 70-85%
What did Baddeley find out about STM coding based on his results?
For STM, participants given List A (acoustically similar) performed the worst, with a recall of only 10%. They confused similar sounding words (e.g recalling ‘cap’ instead of ‘cat’. It seems there is acoustic confusion in STM suggesting STM is coded on an ACOUSTIC basis.
Recall for the other lists was comparatively good at between 60-80%.
What are the strengths of Baddeley’s study?
LABORATORY STUDY = shows causality (cause and effect relationships)
Can be replicated over and over again to check the results because it was done in a lab
What are the weaknesses of Baddeley’s study?
LACKS ECOLOGICAL VALIDITY, not representative of real-life activities
What did Anokhin estimate?
The number of possible neuronal connections in the human brain. He estimated that there are unlimited neuronal connections and therefore the capacity of LTM is UNLIMITED
What did Wagenaar create and test himself on that suggests LTM capacity is unlimited?
He created a diary of 2,400 events over SIX years and tested himself on recall of events rather than dates, finding he had impeccable recall
