Short- and long-term memory Flashcards
What is capacity?
This is a measure of how much can be held in memory. It is represented in terms of bits of information, such as number of digits.
What is coding?
The way information is changed so that it can be stored in memory. Information enters the brain via the senses. It is then stored in various forms, such as visual codes, acoustic codes or semantic codes.
What is duration?
A measure of how long a memory lasts before it is no longer available.
What is long-term memory?
Your memory for events that have happened in the past. This lasts anywhere from 2 minutes to 100 years. LTM has potentially unlimited duration and capacity and tend to be coded semantically.
What is short-term memory?
Your memory for immediate events. STMs are measured in seconds and minutes rather than hours and days. They disappear unless rehearsed. STM also has a limited capacity of about 4 items or chunks and tends to be coded acoustically.
What is the capacity of short-term memory?
Jacobs found that the average span for digits was 9.3 items and for letters 6.3. Jacobs suggested this could because there was only 9 digits and 26 letters. Miller magic 7+/- 2
What is the capacity of long-term memory?
The capacity of long-term memory is potentially infinite.
What is the duration of short-term memory?
Peterson and Peterson used nonsense trigrams to test STM duration. asked to recall a consonant syllable and three-digit number after a duration of 3,6,9,12,15 or 18 seconds. During this they were asked to count backwards from the three digit number to stop rehearsal. 90% correct after 3 seconds but only 2% correct after 18 seconds.
What is the duration of long-term memory?
Bahrick et al. tested ages 17-74 on memory of classmates. They were asked to name as many as they could and then given pictures. People who had graduated within 15 years were 90% accurate with identifying pictures dropped to 70% after 48 years.
How do we code for short-term memory?
Baddeley used word lists to test coding. He found that participants had difficulty remembering acoustically similar words in STM and semantically similar words posed a problem. This suggests short-term memory is largely encoded acoustically.
How do we code for long-term memory?
Baddeley used word lists to test coding. He found that participants had no difficulty remembering acoustically similar words in LTM but semantically similar words led t muddled LTMs. This suggests long-term memory is largely encoded semantically.
What is a negative evaluation of capacity?
One criticism of the research investigating STM is that the capacity may be even more limited than 7+/- 2. Cowan reviewed a variety of studies on the capacity of STM and found that the STM is likely yo be limited to about 4 chunks or information. These results contradict the original findings of Miller. This matters because the original findings have not been replicated by subsequent studies and suggest that STM is more limited than originally thought.
What is a negative evaluation of capacity?
A final criticism of research investigating STM Is that memory improves with age. Jacobs also found that recall increased steadily with age 8-year-olds could remember an average of 6.6 digits, but a 19-year-old could remember an average of 8.6 digits. This increase may be due to a gradual increase in brain capacity. This suggests that the capacity of STM is not fixed and that individual differences play a role.
What is a negative evaluation of duration?
Another criticism of research investigating STM is that the testing methods are artificial. Trying to memorise strings of digits or consonant syllables does not reflect memory in everyday life. Although we do sometimes need to remember meaningless things such as phone numbers or post codes. This matters because the studies may lack mundane realism and therefore ecological validity and it may only be useful when learning certain types of information.
What is a negative evaluation of duration?
Reitman used auditory tones instead of numbers so that displacement would not occur. He found that the duration of STM was longer. This suggests that forgetting in Peterson and Petersons study was displacement rather than decay.
