1. The Cognitive Science Approach
Cognitive Psychology
Chapter 2.4
The Cognitive Science Approach

2. Outline 5/7/2019 Cognitive Science (c’ont) Video “The Name Dropper”
“OK, Mr. Dittmars, remember: That brain is only a temporary, so don’t think too hard with it.”
Outline
Cognitive Science (c’ont)
Methods of investigation
Imaging
> Functional imaging
Electrophysiological recording
Simulation
> PDP
Video “The Name Dropper”
Study Question.
• Compare and contrast the fMRI technique with ERP recording.

3. Results Sections (Part I)
Descriptive and Inferential statistics
Describing data
Verbal
Pictorial

4. Results Sections (Part I)
Descriptive and inferential statistics
Testing McCormick’s Amazing Memory Drug
Percent Recalled
66.0
66.2
Drug
Placebo
66.1 3

5. Results Sections (Part I)
Inferential and descriptive statistics
Sampling error
Are the results do to the effects of the drug or due to luck?
Logic of hypothesis testing
Assume there is no difference (I.e., it is due to chance)
Null hypothesis
What is the probability of getting this big a difference?
The p < .05 convention.
The results of the memory drug experiment are most likely not significant 3

6. Results Sections (Part I)
Analyzing our data
Types of inferential statistical tests
Differences between means and the t-test
Factorial designs: Multiple independent variables
E.g., Handedness by scissors design
Main effects and Interactions
Handedness
Scissors Left Right Mean
Left
Right
Mean
Table 1. Time (secs) to complete a scissors cutting task. 3

7. Results Sections (Part I)
Analyzing our data
Results: Omnibus Analysis (Not this year’s data!)
Comparison analyses 3

8. The Cognitive Science Approach
Methods of investigation
Lesions
Direct stimulation
Imaging and recording
Single cell recording
Imaging
Event-related potentials (ERPs)

9. The Cognitive Science Approach
Methods of investigation
Imaging and recording
Computed Tomography (CT)
Imaging by sections or sectioning using x-rays.
Produces an image of a “slice” or “slices” of the brain
Computer processing used to generate a 3-d image of the inside of brain from the 2-d X-ray images.

10. The Cognitive Science Approach
Methods of investigation
Imaging and recording
Magnetic Resonance Imaging (MRI)
Provides better contrast between soft tissues than CT
Does not need ionizing radiation (contrast agents)
Giant magnet realigns water molecules
Radio frequency electromagnetic field is presented
• H2O protons realign to the EM
• Returns to original alignment when EM is turned off
• Scanner detects signals given off during alignment

11. The Cognitive Science Approach
Methods of investigation
Imaging and recording
Magnetic Resonance Imaging (MRI)

12. The Cognitive Science Approach
Methods of investigation
Imaging and recording
Positron Emission Tomography (PET)
A tracer is used (positron emitting radionuclide), which the scanner detects
Images of tracer concentration in 3D are constructed by a computer
Can be combined with a CT scanner
Can produce 3D image or map functional processes

13. The Cognitive Science Approach
Methods of investigation
Imaging and recording
Positron Emission Tomography (PET)
Mapping function
The left column shows original PET images of the regional cerebral blood flow at rest (top) and during language activation (bottom) . The task was to silently generate verbs from auditorily presented nouns. The right column shows the corresponding cerebral anatomy for that particular slice (top) and the same image with the significantly activated areas superimposed.

14. The Cognitive Science Approach
Methods of investigation
Imaging and recording
Mapping function using MRI (fMRI)

15. The Cognitive Science Approach
Methods of investigation
Imaging and recording
Problems with functional imaging
Modern Phrenology
Reliance on subtractive method
Localized vs. distributed processing
• Communication between regions is important
Indirect measures
• Hemodynamic delays
-> In PET up to 60 s,
-> MRI 2-6 s

16. The Cognitive Science Approach
Methods of investigation
Imaging and recording
Problems with functional imaging
Localization of function
• Blurry resolution & pretty pictures
-> PET cubic mm
-> fMRI 2 mm X 4 mm (a grain of rice)
Called a Voxel (Vo -lume and pi- xel)
-> One voxel contains millions of neurons
Many would have to fire to “light” up the area
What about smaller cell assemblies?

17. The Cognitive Science Approach
Methods of investigation
Imaging and recording
Problems with functional imaging
Localization of function
• Versus individual differences
-> E.g., Six participants in spatial memory task

18. The Cognitive Science Approach
Methods of investigation
Imaging and recording
Problems with functional imaging
Localization of function
• Versus individual differences
-> E.g., Finding the executive
Ridderinkhof’s analysis
38 studies locating the central executive

19. The Cognitive Science Approach
Methods of investigation
Imaging and recording
Finding the executive

20. The Cognitive Science Approach
Methods of investigation
Imaging and recording
Statistical issues
Univariate analysis
Summing in the voxels over time
Corrections for multiple comparisons
The .05 rule, revisited

21. The Cognitive Science Approach
Methods of investigation
Imaging and recording
Statistical issues
Bennet’s study
• Photographs depicting individuals in social situations with a specified emotional valence.
• The participant was asked to determine what emotion the individual in the photo must have been experiencing.
• Subtractive method was used

22. The Cognitive Science Approach
Methods of investigation
Imaging and recording
Statistical issues
Bennet’s study
• Results

23. The Cognitive Science Approach
Methods of investigation
Recording
E.E.G

24. The Cognitive Science Approach
PDP Models
Connectionist/ neural net models
The master spy analogy

25. Perception and Pattern Recognition
Visual agnosia