Research measures and modeling cognitive processes Flashcards
Metatheory
A set of assumptions and guiding principles
Information-Processing approach
The coordinated operation of active processes within a multi-component memory system
- There are sub-processes arranged in stages
Atkinson & Shiffrins multi-store memory model
What methods can we use to obtain scientific evidence on mental processes?
- Response time
- Accuracy
- Verbal reports
Very subjective - Different types of brains scans from neuroscience
Response Time
Time between presentation of stimulus and the response
- Mental effort takes time
- Indirect proof that there are some underlying processes going on
Accuracy
Correct answers
- Correct order
- Recall
- Meanings
Can we inhibit responses that are no longer required, and how?
- With the use of Stop Signal Tasks
- Use of response inhibition
- Control of your impulsivity
There is a cue on the screen, as fast as possible and without making mistakes you respond whats appropriate with the cue. When there is a red guy, you stop. - Measured in milliseconds, very precise
What are the different types of signal tasks?
- Simple one
Stimulus, you press the button - Go/NoGO RT
Green stimulus - you press response button
Red stimulus - Do not press response button
An additional task: Stimulus identification - Extra time shows there is additional processes
- Choice RT
A choice between stimulus. Adds response selection as well as stimulus identification
What is the problems with subtraction methods?
- Requires two tasks
- Difficult to create those two tasks with only one specific process different
What is additive factors method?
A technique used to analyze processing time for specific cognitive tasks
- Factors are components of the process
Smaller cognitive processes
- Measure the overall time
- Understanding different cognitive processing stages
One factor effects one specific stage
Stenbergs Process model - Short term memory
- Memory set in STM
- Encoding probe (time starts here)
Looking for a letter - Scanning and comparisons with memory sets
Search and compare - Binary decision
Is it there? - Execute motor response
Simplified model on how we remember things and how it works - Measures the RT
- If their combined effect to RT is equal to the sum of their separate effects = additive effect
Stenberg Task
- Memory set presented a short time
4 random letters - Indicate whether the following letter was in the previous set by pressing the response button as fast as possible
Different ways of manipulating different stages
- Effects on stimulus quality: manipulate the visibility of the probe. The more degraded the test stimulus, the slower the RT
- Effect on memory load: manipulate size of the memory set (4 letters or 1 letter to remember). The more letters to remember, the slower the RT
- Effect of the duration of memorizing: manipulate when the probe appears. The longer the interval, the slower the RT
How do you infer the additive effects from Stenberg tasks?
- If the lines are parallel with each other, they effect different levels. If the lines cross, there is an interaction
It shows in patterns - Increases the belief that processes are organized serially and selective influence of the factors effect those processes differently
What is the speed-accuracy tradeoff?
A phenomenon where there is a tradeoff between speed and accuracy of performance
Accuracy can vary with response time
- Faster responses can give more mistakes
- Taking time increases accuracy and RT
- Consider mistakes in the results
- How does it influence the cognitive processes?
Try experiments with different age groups
Different measures of accuracy
- Recall Tasks
Performance
% correct answers vs incorrect
Position of words
Grouping
Wrong words - Signal Detection Theory
What is cognitive neuropsychology?
- Study of patients with brain damages to understand how normal cognitive processes works
Split- Brain researchs
- Happened in the 60s
- Corpus callosum surgically cut, lead to the two hemispheres unable to communicate with each other
- Epilepsy patients
Contralaterality
Receptive and control centers for one side of the body are in the opposite hemisphere
Cerebral lateralization
Different functions tend to rely more heavily on one hemisphere or the other, or tend to be performed differently in the two hemispheres
- More tendencies
What are the 3 assumptions came from those split-brain personalities?
- Functional modularity
Cognitive system consists of cognitive modules, independent and each reacting to specific information - Anatomical modularity
Each function is localized in specific part of the brain - Subtractivity
Brain lesions can only affect specific functional modules and patients cant develop new modules to compensate
What has been criticised of these 3 assumptions?
- Cognitive functions are less modular, more parallel processes
- Subtractivity has been challenged due to discovery of brain plasticity
How does one see if there are differences in cognitive processes?
Performance of patients on two or more tasks
- Their performance pattern conclude whether the tasks involve different cognitive processes
Single Dissociation
- No compelling evidence that tasks involve different processes
Start at the same level, poor performance goes down with the second task
Double Dissociation
- Performance on task one and two intersect with each other (X-mark)
- Patients with opposite deficits
- Taken as evidence that these tasks involve different cognitive processes
Association
Lack of dissociation
- Performance on the same level on both tasks
- Possible the tasks relies on the same mechanisms or the patients have the same deficit
What is cognitive neuroscience?
Measures human brain functioning in a non-invasive way
- Electro-magnetic signals produced by the brain
- Changes in blood flow in brain tissues
Gets a large amount of data, increased risk of chance findings
What are the different methods in seeing brain functioning?
- Event-Related Potentional
Shows when changes happens, after presentation
Electrical activity - fMRI
Sees where the function happens in the brain online - EEG
Patterns of brain waves, to indicate mental processes - CT and MRI
Pictures of the brain
Not used as much in modern cognitive science
Connectionist Models
Computer programs that mimic intelligent behaviour
- Very abstract
- Assumes limited capacity with humans
- These models are believed to have the same basic principles as the brain
How does a connectionist model look
- It has nodes
Variable with an activation level - Connection between the nodes
The connection is weighted - positive or negative influence on other nodes
Activation are spread via connections - Input nodes
Stimulus coded in activation pattern - Output nodes
Answer the pattern
Some sort of behaviour
