Short-term Memory / Working Memory Flashcards
Who taught us of memory?
- The patient H.M
Had epilepsy surgery, where hippocampus got removed - Issues with his short term memory
- Could have conversations
- Could remember new information for a short time but could not store it in long-term memory
Visual Persistence
Of visual stimulus beyond its physical duration
- A subjective feeling
- Information can be gathered
Example: Duration of lightning
Iconic memory
Visual info in visual sensory memory
- A temporary buffer
Echoic memory
Auditory info in auditory sensory memory
What is the sensory register/memory?
- Modalic memories stored in different sensory memory, for a very short time
What did partial report studies show?
Evidence that sensory info for a short time is available for further processing
- Around 4-5 items can be stored - span of apprehension
- Decays very quickly
How does partial report studies work?
Phase 1
1. Presentation of a matrix with random letters for a short time
Presentation of 12 letters
2. Which letters were in the previous display (whole report)?
Shows around 4-5 letters
Phase 2 - adding of tunes(cues) to specific rows
1. Presentation of a matrix followed by a cue
Added a delay to see how long the letters stays in memory
2. Which letters were in the cued column?
Without delay - 75% correct answer, more delay the less correct answers
Whole report condition
Report any letters the participants can
Partial report
Report the specific row the letters were in
Icon
The visual image that stay in our iconic memory
Decay
That memories fades away during the course of time
- Old idea
- Spontaneous
Interference
Forgetting is caused by intervening stimulation or mental processing
- Modern approach
Study by Averbach & Coriell*
- Did a partial report study as well but with visual cues instead
- Result; using circle as cues gave less accurate answers than using a rectangle
Backward masking
A later stimulus can drastically affect the perception of an earlier one
- A kind of interference
What is trans-saccadic memory?
The memory that comes from a series of eye movements
- Use of object files
Mental representations of individual objects
- Brain assumes objects are stable
Can miss changes very easily
Simple memory task*
- To see what we can recall in our STM
1. Listen to a series of words
2. Recall them in the exact order of presentation - Serial recall
What is short-term memory span?
The longest list of items that a person can repeat back immediately after presentation, in correct order
- 50% of the trials
Is there a limited capacity in STM?
- There is yeah
Capacity is 7 +/- 2 (though this is arguably a bit too much) - Without chunking, 3-4 units
- STM is the bottleneck in our information processing system
We cant encode vast quantities of info AND hold it accurately
What is chunks?
A way for us to bypass capacity limits by grouping multiple items into a larger, meaningful unit
- A sort of strategy
- Categorising
Recoding
The technical term for grouping items together and then remembering the newly formed groups - The cognitive process
- 2 conditions for this though
1. Enough time or resources to apply a recording scheme
2. The scheme is well-learned from the get-go
Modern research on STM span*
- Presenting a memory array or sample display
Number of different types of shapes or objects - Presenting the test array or test object
Is it different or the same?
Was it in the sample display or not?
- Familiarity with the objects
- Time mattered
Longer time step 1 was presented, time delay between step 1 and 2, how long it takes to answer etc - Localization
- In hopes of avoiding people to chunk information
Free recall task*
- Listening to a series of words
- Recall the words in any order you wish
Primacy effect
- Better memory for first items in a list
Recency effect
Better memory for last items in a list
Serial position curve
Goes down in the middle and then back up in the end
- Shows whats more likely to be remembered
- The accuracy
Studies on primacy and recency effect*
Present a series of word with different length of time till the next word is presented
- Gives time to repeat in your mind
- Or add a light task in between
First items rehearsed and stored in LTM, most recent items still strongly activated in STM - shows that there are different processes involved in primacy and recency effects
Stenberg Task - STM scanning*
- Presenting memory set
1-6 letters or digits - Indicate whether the probe was in the memory set
Half of the trials the probe was in memory set, the other half it wasnt
How does scanning and searching for probes work?
- More interesting for Stenberg
- He had 3 hypothesis
Parallel search
All items in the memory set scanned at the same time
- Pop out- effect
- The number of digits and letters in memory set does not matter
- Not much supporting data for this
Serial search - Self-terminanting
Items in the memory set scanned one by one and stopped when match is found
- 2 separate lines
- No supporting data
Serial search - Exhaustive
Items in the memory set scanned one by one. The entire set gets scanned, even after match is found.
- Data for this was found, that pattern was found
However
- It can still be a parallel search
Brown-Peterson task*
Testing if forgetting is due to decay
- Presented 3 letters
- Distractor task to prevent rehearsal
- Report the 3 letters
if step 2 was for 18s, 5% accuracy on step 3. Shorter time gave higher accuracy on correct answer
- Maybe distractor task is the reason why?
Probe digit task*
- Listening to a list of 16 words
The last number is the probe - Which digit followed the last digit when it was presented before?
Group 1: 16 seconds presentation time
Group 2: 4 seconds
Was there a difference between accurate answers? (if yes, then time matters)
- It was barely a difference
Proactive interference
Previous, older material interferes with recall of current items
Release from PI
Performance returns to higher level of accuracy
Trial 1-3 letters
Trial 4 digits
Retroactive interference
Newer materials interferes backwards in time with your recollection of older items
- Especially when new and old information are similar
Modified Brown-Peterson task*
- Memorize 5 words
- Distractor task between 2-32 seconds
- In which order were the following words presented?
Findings: Decline in memory with increasing recall interval, but at a slower rate than previous Brown-Peterson task
What is working memory?
- An augmentation to STM
- Is used to perform tasks
- Constructed by 3 types of modules
Central executive
Visuo-spatial sketchpad
Phonological loop - They all got some sort of limited capacity
- Alot of active mental processing
- Presented by Baddeley
Central executive
Controls the processing in the other two systems and make sure we can manipulate, maintain and update content of WM
- Attentional controller
- Heart of the WM
Visuo-spatial Sketchpad
Involved in the memory of visual and/or spatial information
- Dissociation between visual memory and spatial memory
Double dissociation - proof
- Visual patterns test
- Corsi block tapping task
Phonological loop
Involved in the memory of auditory, speech-based, information
Consists of two parts
Articulatory loop - Inner voice, active
Phonological store - Inner ear, passive
- The both work together
Dual Task studies - WM*
Highlights that info processed in on system may not interfere with others
- Presents two tasks that interferes with different aspects of WM
Chess players + additional task= what impact does it have on chest players
- Involves storage and processing information
Phonological similarity effect
List of words that sounds similar are more difficult to remember as compared to different words
- Gets confused in phonological store
- We use phonological information when remembering words
Word-length effect
Longer words are more difficult to remember than shorter
- Longer words need more rehearsing
- Capacity of phonological loo is limited by the time words need to be rehearsed
Articularity suppression effect
People have poorer memory of a set of words if they are asked to say something while trying to remember information
- Studying near people who are talking
- Not devastating effect on visual effect
Mental rotation
Turning, rotating or spinning objects in WM
- People can make accurate judgements
Boundary extension
Misremembering boundaries of a scene
- We often think we are further away
- WM adds in extra knowledge about the scene
Representational momentum
Misremembering movements of an object, influenced by embodied aspects
- A ball went further on the screen than reality
What can the central executive do?
- Focusing of attention
- Dividing attention between streams of information
- Switching attention between tasks
- Creating connections with LTM
- Activates the other systems in WM
Episodic Buffer
- Added into the old model by Baddeley 2000
It integrates information from STM with LTM - Connection between VS and PL and LTM
- Storage of integrated episodes that are limited to specific time and location
We often remember events in LTM - Limited capacity
Holds episodes
How can you measure WM capacity?
- Operation span task
- Reading span task
- N-back task
Operation span task*
- Presenting a math task with a word afterwards
Solving the math task - Recall on the words
Number of items varies
Operation span
Largest number of items for which the participant can report all items correctly on at least 50% of the trials
- Either same order or free recall(last words cant be said first)
Working memory span task*
Simultaneous mental processing and storage of information in WM
- Read something out loud while remembering the capitalized words or the final words, and making sure its grammatically correct (reading span task)
Reading span
Largest number of sentences for which the participant can report all final words correctly on at least 50% of all trials
N-back task*
In this task, participants are presented with a series of stimuli, such as letters or numbers, and must indicate whether the current stimulus matches the one that occurred n items earlier in the sequence.
1-back Right after each others
2-back One letter in between probe
