Memory: topic 1 ‘features of STM and LTM’ Flashcards
What is short term memory?
- a temporary store for information
How does information enter the short term memory store?
- if we have paid attention to info in the sensory register (maintenance rehearsal), it will be sent to short term memory
How is information lost from the short term memory store?
- displacement or decay
What is long term memory?
- a memory store that stores information over lengthy periods of time
How does information enter the long term memory store?
- through elaborative rehearsal
How is information lost from the long term memory store?
- retrieval failure or interference
What is capacity?
- how much information the store can hold
What is duration?
- how long a memory can be held for
What is coding?
- the way information is transformed into a format that can be stored and retrieved from memory (eg visual, acoustic, semantic)
What is the capacity and duration of short term memory?
- capacity: 5-9 items
- duration: 18-30 seconds
How did Miller use the digit span technique to prove the short term memory has a limited capacity?
- he used the digit span technique which is a series of digits that get progressively longer
- the participant is asked to IMMEDIATELY repeat the digits back in order
- Miller found that participants on average could recall 5-9 items
- he also found that the capacity of the stm can be increased by chunking
What is the capacity and duration of long term memory?
- capacity: unlimited
- duration: up to a life time
How did Bahrick use the free recall test to prove the long term memory has an unlimited duration?
- he asked 392 participants aged 17-24 to name old classmates from highschool
- they were then given 50 photos and asked if they could recall their names
- they found that 15 years after graduation, free recall was about 60% accurate, but after 48 years this dropped to 30%
- recognition was 90% accurate after 15 years but only 70% after 48 years
- this suggests ltm could have a potentially unlimited duration and that even if a long term memory cannot be freely recalled, this does not mean it is no longer stored, it may just need assistance to be
What coding is used in short term memory?
- acoustic (sound)
How did Baddeley use word lists to prove the coding of short term memory was acoustic?
- participants were presented with a list of words that were acoustically similar (eg cat cab can) and asked for immediate recall
- these participants made more errors than they did when presents with a list of acoustically different words (eg pit few cow)
- he concluded that this was because there was confusion based on the way words sounded
- this suggests that stm encodes information acoustically
What coding is used in long term memory?
- semantic (meaning)
How did Baddeley use word lists to prove the coding of long term memory was semantic?
- participants were presented with a list of words that were semantically similar (eg great big large) and asked for recall 20 minutes later
- these participants made more errors than they did when presents with a list of semantically different words (eg good huge hot)
- he concluded that this was because there was confusion based on the meaning of words
- this suggests that ltm encodes information semantically
One strength of research into memory (miller and bahrick)
- high control over variables
- conducted in a laboratory setting with control over extraneous variables (eg same environment and noise levels)
- positive as it avoids participant bias
Another strength of research into memory (baddely)
- easy to replicate
- controlled setting of a laboratory so the conditions used for one study can be used again for further replications
- eg same word lists used in several trials of the same study
- positive as the research can be checked to ensure reliability
One limitation of research into memory (miller and baddely)
- materials used are meaningless
- they do not reflect much of the kinds of information we use our STM and LTM for remembering in the real world
- eg remembering word lists, numbers or similar sounding words does not reflect real life memory activities where what we are trying to remember is often more meaningful and varied
- this is a problem as the findings may not be representative of real life STM and LTM use
How did Peterson and Peterson conduct research into the capacity of short term memory?
- asked 24 participants to listen to a ‘consonant trigram’ (a random string of 3 letter such as ‘WRT’)
- immediately after hearing them they heard a random 3 digit number and were asked to count backwards in 3’s from this number to prevent rehearsal of the trigram
- asked to recall the trigram after 3,6,9,12,15 or 18 seconds
- found the highest level of recall was after 3 seconds (90%) but this decreased as the duration increased, 2% recall at 18 seconds
