Memory Flashcards
What is cognitive psychology?
looks at internal mental processes to explain behaviour
what is encoding and what are the 3 types
encoding is the form in which the brain handles data
it can be acoustic (inner voice)
visual (minds eye)
semantic (based on meaning)
Draw a diagram of the Multi Store Model
diagram involving -stimulus -sensory register (iconic, echoic, other) -STM (response out) -prolonged rehearsal, maintenance rehearsal -LTM -retrieval
What is the sensory register - its capacity, duration and other points
Sensory registers are the memory store for the 5 senses such as vision (an iconic store) and hearing (an echoic store)
Coding is different for various sensory registers - in the iconic store coding is visual but in the echoic store coding is acoustic
Sensory registers have a very high capacity but hold information for less than 1/2 a second
information from sensory registers only passes further If you pay attention to that info
An experiment to test duration of sensory register
Sperling’s experiment
Procedure:
Sperling flashed 12 letters in a grid on to a screen for a very short amount of time
Test 1: ppts recorded as many letters as they could
Test 2: after the letters disappeared Sperling would request only the letters on one line of the grid
Results of Test 1: 4-5 out of 12 total letters were recorded; about 33%
Results of Test 2: 3 out of 4 letters to recall were recorded; about 75%
Conclusion: This suggests the sensory register was picking up about 75% of the total 12 letters, yet the ppts could not record all 9 letters before the information was lost. This shows the duration is about 1/2 a second long.
The case of HM - who is he and what did the studies show
HM suffered from epilepsy. He had his hippocampus removed from both sides of his brain. The hippocampus is now known to be very important for memory function. His epilepsy stopped, but he lost his LTM. He could not remember the operation or anything since. His LTM was repeatedly tested but never improved. Despite this, he performed well on STM tasks. The study of HM supports the MSM as it provides evidence for having two separate memory stores.
A criticism of the study of HM is that he was a brain damaged patient and so the evidence may not be true for other people (low population validity), weakening his support for the MSM.
Experiment for capacity of STM
Jacobs (1887)
Procedure: Read out 2 letters / digits to ppts and ask them to recall them in the correct order. If they correctly do that move on to 3 letters / digits and so on.
Results: The mean span for digits was 9
The mean span for letters was 7
Evaluation: a very old study and may have lacked adequate control
increasing capacity of STM
MSM
Miller (1956)
capacity of STM can be increased by combining separate bits of information into larger chunks.
Experiment for duration of STM
Peterson and Peterson (1959)
Procedure: tested 24 students who each took part in 8 trials. Each student was given a trigram and then asked to count back from digit in 3’s. On each trial they were asked to stop after a different time interval. This prevented mental rehearsal of the trigram.
Results: the %age of correct responses decreased as the retention interval increased. After 18 secs only 13% was recalled
conclusion: STM has a duration of about 20 secs unless we verbally rehearse the information.
Evaluation: lacked external validity.
experiment for duration of LTM
Bahrick (1975)
Procedure: studied almost 400 Americans. High school yearbooks were obtained and the ppts were tested on:
Test 1: photo recognition where some but not all of the photos were from the yearbook
test 2: free recall where ppts recalled names from their graduating class
Results for test 1: ppts tested within 15 years of graduating had a 90% accurate recall rate. after 48 years recall rate dropped to70%
results for test 2: ppts within 15 years were 60% accurate dropping to 30% after 48 years.
Conclusion: LTM has a lifetime long duration
what is the capacity, duration and coding for the Sensory register, STM and LTM
(MSM)
Capacity: SR: 9 letters (Miller) STM: 5-9 letters LTM: unlimited Duration: SR: 0.5s STM: 20s (Peterson and Peterson) LTM: lifetime (Bahrick) Encoding: SR: different for different registers - visual or acoustic mostly (Sperling 1960) STM: acoustic (Baddeley and Conrad) LTM: semantic, episodic and procedural
Experiment for coding in STM and LTM
Baddeley (1966)
Procedure: gave lists of different words to 4 different groups
group 1: acoustically similar
group 2: acoustically dissimilar
group 3: semantically similar
group 4: semantically dissimilar
Test 1: ppts had to recall the words in the correct order immediately (STM)
test 2: ppts recalled words after 20 mins (LTM)
results:
Test 1 was worse with acoustically similar words suggests STM codes acoustically
test 2 was worse with semantically similar words suggesting LTM codes semantically.
Evaluation: high internal validity - well controlled
low external validity - artificial task
2 types of rehearsal in MSM
Maintenance - maintains information in STM and does not move it to LTM
prolonged / elaborative - adding meaning to information so it can be moved to LTM
study of KF and what he shows about MSM
how does KF support the WMM
Shallice and Warrington (1970) studied KF - a patient with severe amnesia.
His STM was very poor when digits were read aloud to him (acoustic). However it improved when he read the digits out to himself. Further studies showed there could be another STM store for non-verbal sounds. The MSM doesn’t account for separate STM stores for different types of information.
KF couldn’t process verbal information but could process visual information. this suggests his phonological loop was damaged but his VSS was intact. This suggests there are 2 separate STM stores as the WMM shows
Definitions of episodic, procedural and semantic memory.
All types of LTM coding
episodic: memory store for personal events. ‘time stamped’. uses conscious effort to recall.
Semantic: memory for knowledge and facts. has no ‘time stamp’. usually take conscious effort to recall.
procedural: memory store for actions (how to do things) doesn’t use conscious effort to recall.