Short Term Memory Pt 2 Flashcards
(27 cards)
Miller (1956)
- Identified a pattern in his own research that the number 7 (plus or minus 2) was frequently reported as a finding in short-term tasks
How do we test STM?
Memory Span – The number of correct items that people can immediately recall from a sequence of items
(ie Digit span task, backward digit span task)
What do we mean by 7 items?
It is based on how you group the units.
** Not necessarily the number of digits.
Miller (1956) – Chunking
Chunks consist of individual items that have been learned and stored as a group when integrating into LTM
- He proposed that STM should be measured in chunks rather than items
STM Capacity and Correlations
In 1980, Daneman & Carpenter showed that estimates of capacity on a reading span task predicted/correlated reading comprehension
Examples of correlates of higher capacity estimates
- Problem solving
- Fluid intelligence
- Reduced interference on a stroop task
- Reduced cocktail party effect
- Proactive control
- Better control of attention
** Don’t need to memorize all of these**
De Groot (1966) – Spatial Memory
- Experiments that required players of different abilities to reproduce a chessboard as it might appear late in a chess game
- Guess the placement on the board = Spatial memory
1. Participants viewed the board for a short time
2. Incorrectly placed pieces were removed and participants had to put them back into place
Results of De Groot (1966)
- The masters did much better than the weak players in terms of accuracy (since they relied on their knowledge of rules more)
Why was De Groot (1966) not what they were searching for?
Using prior knowledge of rules (pulling from LTM) is not measuring participants’ STM.
Chase and Simon (1973)
- Extended De Groot’s experiment
- Assumed that pieces belonging to the same chunk would be placed on the board as a group
- Believed that each item would be the couple of pieces before pausing
- Use of chunking determines the success
Conclusions of Chase and Simon (1973)
Concluded more skilled players were more successful in reproducing the chess board because they had more chunks and more pieces per chunk
- The estimated number of chunks across the three skill levels fit within the range 7 +/- 2 as proposed by Miller
Sternberg (1966)
- Showed a sequence of numbers (the memory set) to the participants, who had to determine if a given number was in the memory set
- The time required to make the decision increased when there are more numbers in the memory set
- Participants stored these numbers in their STM and had to retrieve them
What are the 2 types of searches?
- Self Terminating Search
- Exhaustive Search
What is Self-Terminating Search
A search that stops as soon as the test item is successfully matched to an item in the memory set
- Should be able to do it quicker when things are easier to find (think of grocery bag example)
What is a grocery bag example of the Self-Terminating Search?
When looking for the can of tomato sauce, you stop looking only when you find it
What is Exhaustive Search
A search that continues until the test item is compared with all items in the memory set
What is the grocery bag example of the Exhaustive Search?
When looking for the can of tomato sauce, you take everything out even when you find the tomato sauce can
Results of Sternberg (1966)
Response times for whether or not the number was found were approximately the same
- He found that response times were not influenced by the location of the matching digit in the memory set
What kind of search is present in the results of Sternberg (1966)?
Exhaustive Search!
People actually scanned the entire memory set rather than stop when they found it
Baddeley and Hitch (1974)
Created a model for working memory (think an elevated version of STM)
Consists of the (1) phonological loop (2) visuospatial sketchpad (3) central executive (4) episodic buffer
Phonological Loop
Auditory working memory
- Is responsible for maintaining speech-based info (think of phone)
Visuospatial Sketchpad
Visual working memory
- Responsible for maintaining visual or spatial info (think of mentally refreshing an image)
Central Executive
Responsible for selecting strategies and integrating information
- Helps us memorize and organize information
- The only system that talks to all the other systems (the ult)
Episodic Buffer
Serves as a limited capacity store that can integrate information from the visuospatial sketchpad and the phonological loop
- Receives from the CE to prepare for LTM
