Psych. 421 - Sensation and Perception

Study Notes

Dr. Carpenter

CHAPTER 1-4

Revised 8/98

A general note: be certain to know and understand the terms listed in the "New Terms" section of each chapter.

   Also, don't overlook the chapter outline at the beginning of each chapter, the section summaries, and the review questions at the end of each chapter.

I.  Chapter 1 - Introduction

A. Know the overview of the 6 approaches to sensation and perception given in this chapter.  Watch for evidence of them in future chapters.

B.  Be familiar with the 4 themes for the book that are presented.  Watch for evidence of them in future chapters, as well.

II. Chapter 2 - Perceptual Methodologies

     A. What is psychophysics?

     B. Classical Psychophysics

              1. What is the absolute threshold, and how is it measured?

              2. Method of limits

              3. Method of constant stimuli

              4. Method of adjustment

              5. What are these methods and how do they differ from each other?

              6. What is the difference threshold, and how is it measured?

              7. What is a JND?

    C. Signal Detection Theory

              1. What does it do that classical psychophysics doesn't?  hint: sensitivity & criteria

              2. How does the experimental procedure differ from that of classical psychophysics?

                       a. What are the 4 possible outcomes of a trial?

                       b. How can criteria be manipulated?

                       c. How can sensitivity be manipulated?

                       d. What does an ROC curve show?

     D. What does a psychophysical function do?

              1. Weber's Law

                        a. What is it?

                        b. Is it any good?

              2. Fechner's Law

                         a. What is it?

                         b. Is it any good?

              3. Steven's Power Law

                          a. What is it?

                          b. Is it any good?

III. Chapter 3 - The Visual System

     A. What is the stimulus?

              1. Electromagnetic radiation

              2. wavelengths

              3. amplitude

      B. The sensory organ - the eye

             1. Structure of the eye - see figure 3.5

                          a. Astigmatism

                          b. glaucoma

             2. The retina

                          a. Photoreceptors - rods and cones

                          b. Duplicity Theory - how the functioning of the rods and cones differ

                          c. Sensitivity to light

                                       i) Adaptation

                                      ii) Sensitivity of rods and cones is a function of wavelength

                          d. Distribution of rods and cones over the retina

                          e. Where the impulses go from there? - bipolar and ganglion cells

                          f. Receptive fields - What are they?

                          g. X, Y, and W cells - ditto

                          h. The amacrine and horizontal cells - going sideways

              3. Visual pathways to the brain - what are they?

                          a. Two Parallel Visual Pathways

                                       i) midget ganglion cells - parvo pathways

                                      ii) parasol ganglion cells - magno pathways

                          b. Optic Chiasm

                          c. Optic Tract

                          d. Superior colliculus

                          e. Lateral Genculate Nucleus

             4. Visual Cortex - Areas 17, 18, 19, each with 8 layers

                          a.  Retinotopic

                          b. Cortical magnification

                          c. The cells - discovered by whom?

                                       i) Simple

                                      ii) Complex

                                      iii)     Hypercomplex

                          d. The organization - How is it laid out in Area 17?

                                       i) orientation specific column - orientation tuning curve

                                      ii) ocular dominance

                                      iii)  retinal location

                                      iv)   hypercolumn

                                      v) blobs and interblobs

                          e. Areas V2 - V5

                          f.  Inferior Temporal cortex

                          g. Disorders

IV. Chapter 4 - Basic Visual Functions

     A. Requirements for Normal Vision

             1. Edges and contours are amplified in vision

                          a. Mach Bands

                          b. Lateral Inhibition

             2. Change - how and why?

                          a. Involuntary motions

                                       i) Microsaccades

                                      ii) Drifts

                                      iii) Physiological Nystagmus - tremors

                          b. Stabilized Retinal Image

              3. Higher Level Processes - (higher?)

                          a. The missing blind spot

              4. Experience

      B. Lightness Perception

              1. Lightness Perception 

                          a. Albedo

                          b. Lightness Constancy - What is it?

                          c. Proximal and Distal Stimuli

              2. Explanations for Lightness Constancy

                          a. Helmholtz - unconscious use of illumination

                          b. Wallach's Ratio Principle

              3. Perceptual Organization before Lightness Constancy

                          a. Gilchrist - role of perceived distance

               4. Exceptions to Lightness Constancy

                          a.   Gelb's experiment

                          b. Mach's book

    C. Acuity - What is it?

              1. How is it measured? - Visual Angle

              2. Factors Affecting Acuity

                          a. Characteristics of the Eye

                                       i) Location on retina

                                      ii) Pupil diameter

                                      iii) Luminance

                          b. Accommodation - What is it and how does it work?

                                       i) emmetropic = normal

                                      ii) myopic = near-sighted

                                      iii) hypermetropic = far-sighted

                          c. Stimulus Characteristics - luminance and glare

     D. Motion required for vision - moving the "camera"

              1. Voluntary movements

                          a. Version Movements

                                       i) Saccades - fixation pauses

                                      ii) Pursuit Movements

                          b. Vergence Movements

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