Memory: Short and Long term memory Flashcards
Define memory
A process in which info is retained about the past
What is LTM?
The memory of events that happened in the past.
What is STM?
The memory of immediate events.
Also referred to as the working memory.
Define capacity
How much data (info) is stored
Define coding
How info is stored/recorded
Define duration
How long info can be stored in memory
Who researched capacity?
Jacobs (1887)
Miller (1956)
What was Jacobs (1887) research into capacity?
Used digit span.
The ppts had to immediately recall a sequence of letters/ numbers which increased by one item each trial.
What were the findings pf Jacobs (1887) research
Found that the avg. Span for digits was 9.3 for numbers + 7.3 for letters (presumably because there’s only 9 different digits but 26 different letters)
What was Miller’s research into the capacity of the STM?
Created an article after reviewing psychological research + it’s findings
Call it a review and not a meta-analysis
What were the findings of Miller’s research?
People can typically remember 5 – 9 items (leading to the idea of the magic number 7±2).
He also found that people can recall 5 letters as well as they recall 5 words by chunking things together.
What is the capacity of the STM?
7±2 as proposed by Miller (1956)
What is the capacity of the LTM?
Potentially infinite
What are the 3 AO3 points for capacity of STM?
-Lack of clarity in Miller’s research
-Capacity maybe more limited
+Methodology in Jacob’s research
(-AO3) What is the lack of clarity in Miller’s research?
Miller’s definition of a “chunk” is vague leading to confusion + inconsistency in subsequent research. It’s unclear whether a chunk represents a single letter, word, phrase or some other unit of info.
(-AO3) How may capacity be more limited?
Further research on capacity of STM showed that it’s likely to be roughly 4 items. This means the lower end of Miller’s range is more appropriate (7 – 2 = 5). Suggests that STM may not be as extensive as Miller thought.
Who researched duration in the STM?
Peterson + Peterson (1959)
What was the procedure of Peterson + Peterson’s study (1959)
24 ppts tested over 8 trials.
On each trial a ppt was shown a consonant syllable + a 3-digit number (e.g. THX 512).
Ppts were asked to recall the consonant syllable after a retention interval of 3, 6, 9, 12, 15, or 18 secs. During the retention period ppts were asked to count down from their 3 – digit number.
What were the findings of Peterson + Peterson’s study (1959)
Ppts on avg. 90% correct after 3s
20% after 9s only
2% after 18s
Suggesting that STM has a very short duration (approx. 18-30 secs) if verbal rehearsal is prevented.
What are the 2 AO3 points for Peterson + Peterson’s study (1959)
-Lacks mundane realism
-STM results may be due tp displacement
(-AO3) How does Peterson + Peterson’s study (1959) lack mundane realism?
The Petersons study used simple tasks, such as recalling random strings of numbers + letters.
It’s unclear whether these tasks reflect real – life situations in which STM is used such as remembering telephone numbers or a grocery items.
(-AO3) Why could STM results be due to displacement?
Petersons’ ppts were counting the numbers in their STM + this may displace the syllables to be remembered.
Reitman (1974) used auditory tones instead of numbers so that displacement wouldn’t occur (sounds don’t interfere with verbal rehearsal) + found that duration of the STM was longer.
Which suggests that forgetting in P+P’s study was due to displacement rather than decay.
Who investigated duration of the LTM?
Bahrick et al. (1975)
What was the procedure of Bahrick et al’s research (1975)
400 people aged 17 –74 on memory of classmates.
A photo – recognition test consisted of 50 photos, some were from the ppts high school yearbook.
In a free-recall test ppts were asked to list the names if those they could remember from their graduating class.
