The Cognitive Science Approach Cognitive Psychology Chapter 2.4 The Cognitive Science Approach

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.

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

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

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

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 2 12 7 Right 8 2 5 Mean 5 7 6 Table 1. Time (secs) to complete a scissors cutting task. 3

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

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

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.

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

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

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

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.

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

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

The Cognitive Science Approach Methods of investigation Imaging and recording Problems with functional imaging Localization of function • Blurry resolution & pretty pictures -> PET 6 - 9 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?

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

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

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

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

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

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

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

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

Perception and Pattern Recognition Visual agnosia