Short term memory Flashcards
1
Q
What is short term memory and long term memoeru?
A
- Short term memory holds information only very briefly, and has severely limited capacity
-Long term memory holds information over long periods, and has potentially unlimited capacity
2
Q
What is short term memeory good for?
A
- It is good for any complex cognitive task that appears to require short-term storage of information
E.g : Arithmetic (3x7-5+10), Language (who is he referring to in a paragraph), Vision (navigating in space)
3
Q
What is the capacity of short term memory?
A
- Individuals can hold approx 7 items simultaneously in short term memory
- Capacity is largely independent of the nature of items e.g digits, letters, words
- Capacity is less than 7 for items that don’t mean anything, e.g words that aren’t real
- If possible, short-term memory makes contact with representations that are permanents stored in our minds
4
Q
What is the digit span task?
A
- Commonly used in IQ tests , used as a screening test for clinical impairments (e.g dementia)
- Includes reading out 3 digits in a monotonous voice, one digit per second
- If correctly recalled, increased to four, etx
5
Q
What is a ‘superspan’ list task?
A
- Presents lists longer than max capacity of 7, and it is a free recall task so can recall list in any order
- Then after many trials, we can plot average recall probability (y-axis) dependant on list position (x-axis) ( The serial position curve)
- Plotting shows, when position is earlier, the recall probability is higher - which is primacy effect - reflects LTM as earlier items undergo more rehearsal
- Later position is the recall probability is higher - recency effect - reflects contribution of STM as the later positions are stored in short term
- It was investigated to try eliminate the STM effect, so the participant was made to perform a task after list, e.g count to 10 and this changed plot and got rid of the recency effect
6
Q
How does Acquired brain damage affect short-term memory?
A
- Milner suffered from intractable epilepsy and hard parts of his temporal lobe (hippocampus) surgically removed
- After he showed defective LTM learning so had an inability to acquire new informations post surgery (Anterograde amnesia)
- His short term memory was fine tho!
7
Q
Are short term memory and Long term memory associated
A
- E.g brain damage followed a motorbike accident (Shallice and Warrington)
- The Long term memory performance was in normal range
- The short term memory was dramatically impaired, so the usual 7 span turned to 2
- Evidence suggests that Short-term memory and long-term memory are separate memory systems
8
Q
What is the modal model of memory?
A
- Environmental input → Sensory registers → Short term memory/ Long term memory → Response output
- Shows for information to enter the short-term memory, it must pass through short-term memory
-Information in the short-term memory can be ‘refreshed’ by means of rehearsal
-The longer an item is held in short-term memory, the more likely to be transferred to long-term memory
9
Q
What did Baddeley and Hitch investigate?
A
- Wanted to test the role of short-term memory and did this by giving two tasks to participants
- the reasoning task was asking participants to verify sentences that describe two successive letters and concurrently they were asked to remember a list of random digits
- The results was that performance times increased by up to 35% however, overall performance was surprisingly good
10
Q
What model did Baddeley and Hitch propose?
A
- The working memory model which suggests that short-term memory consists of more than one component, hence if one component isn’t working, neuropsychological patients may have a component that does work.
- Also explains why the results from their tasks were good, as both tasks may use up different components
- So there is a central executive which integrates information
-Then two peripheral systems:
1) visuo-spatial sketch pad: which is the short-term memory store which processes visual and spatial info
2) phonological loop: the short-term memory store for verbal and auditory info (speech-based codes)
11
Q
What is the central executive?
A
- ‘Mental workbench’ - so it retrieves info from LTM and allows subsequent manipulation
-it regulated information flow between the other components of the working model - ‘Amodal’ so it isn’t tied to specific modality (verbal, visual etc)
- It is constrained by the available capacity as the more demands placed on the system, the less efficient it will perform
12
Q
What is the visuo-spatial sketchpad?
A
- It specialised in the temporary holding and processing of visual and spatial codes
- E.g remembering shapes and colours, tracking moving objects in space, planning spatial movements and navigating environment
13
Q
What is the phonological loop?
A
- It specialises in the storage of speech-based code
- It more or less corresponds to what had been traditionally studied in the Short-term memory research (e.g digit span task)
- The phonological loop has severely restricted capacity
14
Q
What is the capacity of the short-term memory?
A
- There was a traditional view that short-term memory has a capacity of 7, so that it is limited by a fixed number of items
- Baddeley had a more recent view that there is no inherent limitation of the phonological loop capacity, and rather the capacity is constrained by the time it takes to report the items
- So the measured capacity is determined by the number of items that can be reported before they are lost from the phonological loop
15
Q
How did Baddeley investigate the capacity of the short-term memory?
A
- He presented 5-word lists, words ranging in length from 1 to 5 syllables
- The participants either recalled the lists or read them out aloud
- The recalling led to conclusion that short words where better recalled than long words - words length effect
- The reading speed said that short words take less time tp read than long words
- So the amount of items correctly recalled is not 7, but whatever can be uttered in about 2 seconds
16
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