Memory Flashcards
Capacity, duration and coding of the sensory register
- Large capacity
- Duration of 1-2 seconds
- Sensory code
Capacity, duration and coding of the STM
- Limited capacity (found to be around 7 items)
- Limited duration
- Mainly acoustically coded
Capacity, duration and coding of the LTM
- Very large capacity
- Very long duration
- Semantic coding
Who came up with the multi-store model of memory?
Atkinson and Shiffrin
Who carried out research into the capacity of short term memory?
Jacobs, 1887
What was Jacobs’ experimental method?
- Asked ppts to recall strings of letters or numbers of different lengths
- Measured how many they could recall
Jacobs’ experiment: results
Participants could recall an average of 7 letters or numbers, concluding the STM has a limited capacity
Who investigated the sensory register?
Sperling, 1960
Sperling: method
- Presented ppts with a grid of letters for just 50 milliseconds
- Immediately tested their recall
- Two conditions: recall everything, recall one row, specified after seeing grid
Sperling: results
- First group (recall everything) managed to recall 5 letters (40%)
- Second group (row specified after seeing) managed to recall 3/4 (75/100%) letters
- He argued that in condition 2 they had to remember all the rows to answer for just one, indicating the capacity of the sensory register was large but duration very short
What research provided evidence for the presence of two seperate memory stores?
Glanzer and Cunitz (1966)
Glanzer and Cunitz - method
- Serial position experiment
- Ppts hear a list of words and are asked to recall them in any order (free recall)
- Condition 1 was immediate free recall
- Condition 2 was recall after an interference task
- To obtain results he plotted the position of each of the words in the list against how many ppts recalled it
Glanzer and Cunitz: results
- Ppts recalled more words at the beginning of the list (primacy effect, LTM storage) and at the end of the list (recency effect, STM storage)
- The interference task (designed to prevent STM rehearsal) removed the recency but not the primacy effect
- This indicates we have two seperate memory stores
Evidence for the duration of STM: Which research?
Peterson and Peterson
Peterson and peterson: method
- 24 psychology students had to recall meaningless 3 letter trigrams at different time intervals
- They had to count backwards in threes or fours from a specific number until they were asked to recall to prevent rehearsal
Peterson and Peterson: results
- The longer the time between learning and recall, the lower the accuracy
- At 3 seconds, 80% were correctly recalled
- At 18 seconds only 10% were recalled
Peterson and Peterson: evaluation
- Demand characteristics due to all ppts being psychology students
- Lack of generalisability - psychology students at Indiana University may have above average memory function
- Lab experiment - high control, low ecological validity
Quickfire study: duration of long term memory
- Bahrick (1975)
- Tested recall and recognition of the names of their high school classmates
- 15 year recall 60% recognition 90%
- 48 year recall 30% recongnition 80%
- LTM has long duration but recognition is better than recall
Quickfire study: Evidence for coding
- Baddeley (1966)
- Recall 4 lists of words that either sounded similar, different, similar meaning or different meaning
- Ppts recalling acoustically similar struggled more immediately after learning, but 20 mins after learning semantically similar words proved harder to recall
- Concluded STM is coded acoustically and LTM semantically
Case study to support the MSM?
- Henry Molaison, damage to his LTM store but still had a functional STM, indicating that the stores are separate
Brain imaging study support for MSM
- Brain imaging studies have shown that different areas of the brain are active when we hold information over short and long time periods
- Frontal cortex active for STM
- Hippocampus active for LTM