L9 - Short Term Memory Flashcards
Where is short-term memory (STM) in the three-stage model of memory?
Second Stage
What is STM’s capacity?
7 +/- 2
What task demonstrated STM’s capacity?
The Digit-Span Task
(Participants read back, in order, a sequence of numbers that has been read to them)
What is ‘chunking’ information?
Re-coding information to make it easier to remember
(Instead of 8-3-3-8-7-5-8-7, 8338-7587)
What is the time duration of STM?
Around 20-30 seconds
How do we prolong information in our STM?
Rehearsal (repeating the information over and over again)
Do this long enough and it will enter long term memory
What does Decay Theory suggest about forgetting?
Forgetting is a function of the amount of time an item is held in STM.
(When information first enters, it has strong representation, but this decays over time)
What is the Brown-Peterson task?
A simple letter trigram (e.g. TDJ) is presented to the participant followed by a number (e.g. 45)
The participant is then asked to count down from the number in threes (45, 42, 39 etc) until they stop, then they are asked to recall the trigram.
What do the results of the Brown-Peterson task suggest?
That mean performance degrades as a function of the length of time you are counting down.
After three seconds accuracy had dropped to less than 50% correct.
What was the Waugh and Norman (1965) probe light experiment?
Participants are read lists of 17 digits and then followed by a probe light. The probe light digit was a number in one of the 16, it was the participant’s task to say the number after the probe light.
(E.g. 1-5-6-4-2…, probe light is 5, participants should recall 6)
What were the results of the Waugh and Norman probe light experiment?
Did it support decay theory?
The results showed forgetting varied as a function of the location of the probe digit in the list.
This did not support decay theory, as decay would predict a time-based process.
What theory was born out of the Waugh and Norman (1965) experiment?
Describe it briefly
Interference Theory
We lose access to information stored in STM because other information interferes with it.
(e.g. digits presented in 14th place were easier to remember than 3rd place because there were less numbers to interfere with it)
What is proactive interference as described by Keppel and Underwood (1962)?
Previously learned trigrams interfered with the subsequent trigrams - this is proactive interference
(Performance on the Brown-Peterson task varied as a function of the number of trials the participant had performed.)
What is retroactive interference?
Where newly learnt information interferes with previously stored information
How did Wickens et al (1963;1972) demonstrate the phenomenon of release from proactive interference?
They used three trials of the Brown-Peterson task using trigrams.
Following this, the control group received a fourth trial of trigrams whereas the experimental group received a fourth group of numbers.
The performance of the control group declined and the experimental group became almost perfect.
How did Wickens test the release from proactive interference using semantic categories?
What were the results?
The first three stimuli presented involved remembering fruits,
The fourth was either another fruit in the experiment,
or flowers (less similar) or professions (dissimilar) in the control.
The strength of the release from proactive inhibition varied as a function of related concepts.
(Less similar concepts would be remembered more easily)
In free recall tasks, what is the serial position effect?
We tend to see primacy and recency effects in free recall tasks.
Items in the middle tend to have a low probability of recall.
Primacy: Refers to items being easier to remember earlier on the list.
Recency: Items being easier to remember later on the list
What is the process called described by Steinberg that we use to search for memory?
Serial exhaustive search
RTs varied as a function of set size, yes or no answers were almost identical.
