Short and Long term memory Flashcards
What does capacity refer to in memory?
The measure of how much can be held in memory - represented in bits of info such as numbers of digits.
What is the capacity of the LTM?
Potentially infinite
Who assessed the capacity of the STM?
Joseph Jacobs (1887)
How was the capacity of the STM assessed?
Using digit span
What were the findings of Joseph Jacob’s research into the capacity of the STM?
The average span for digits was 9.3 & 7.3 for numbers.
Presumably, because there are 26 different letters compared to 9 different digits.
What did George Miller (1956) find in relation to the capacity of the STM?
Wrote an article called ‘The magic number’ after reviewing psychological research + concluded that the span of immediate items is approx. 7. He noted that ppl could count seven dots flashed onto a screen but not much more than that, which is the same for musical notes, letters and words. thus resulting in the magic number 7 +/- 2.
Miller also found that ppl could recall 5 words as well as they can recall 5 letters suggesting that we chunk things together + can remember more.
AO3: Capacity of STM - individual differences
STM capacity can vary between individuals, with some people having a larger capacity than others. This may be related to factors such as age, intelligence, and cognitive abilities. For example, research has shown that younger adults tend to have a larger STM capacity than older adults.
AO3 weakness: Capacity of STM - interference
STM capacity can be affected by interference, which is when competing information interferes with the ability to remember information. For example, if a person is trying to remember a phone number while also listening to a conversation, the conversation may interfere with their ability to remember the number. This can lead to decreased STM capacity and difficulty in remembering the information.
AO3 weakness: Capacity of STM - more limited
Miller’s original findings haven’t been replicated. Cowan (2001) reviewed a variety of studies on the capacity of the STM + found that STM is likely to be limited to about 4 chunks. Vogel et al. (2001) conducted the same research on visual memory and also found that the limit was approx. 4 items. Making the lower end of Miller’s range more accurate.
What is duration in memory?
A measure of how long a memory lasts before it’s no longer available.
Who studied the duration of STM?
Peterson and Peterson (1959)
What was the procedure of Peterson & Peterson’s study on the duration of the STM?
24 students
ppts tested over 8 trials
On each trial, ppts were given a consonant syllable + a 3-digit number (e.g. THX 512)
Asked to recall the consonant syllable after a retention of 3,6,9,12,15 or 18 secs
During the retention interval ppts, were asked to count backwards from their 3-digit number.
What were the findings of Peterson & Peterson’s study on the duration of the STM?
90% correct over 3 secs
20% correct after 9 secs
2% correct after 18 secs as long as verbal rehearsal was prevented.
AO3 strength: Duration of STM - Control of extraneous variables
One strength of the study is that it used a controlled laboratory setting to minimise the impact of extraneous variables that could affect the results. The use of a metronome ensured that participants counted at a consistent pace, and the use of random letter sequences controlled for any potential effects of stimulus order or familiarity.
AO3 weakness: Duration of STM - Limited generalisability
One limitation of the study is that the sample was relatively small and consisted only of undergraduate psychology students. This limits the generalisability of the findings to other populations, such as older adults or individuals with memory impairments.
