What to Know: Part I

Can You Do These Things?

• Sketch and label the general model of sensation and perception presented in lecture.
• Explain the general model of sensation and perception.
• Distinguish between sensation and perception and give examples of each.
• Explain the difference between top-down and bottom-up processing and give examples of each.
• Sketch and explain the model of information processing presented in class.
• Explain what psychophysics is, including its three basic problems.
• Explain what an absolute threshold is and give some examples.
• Describe how a researcher might find someone's absolute threshold using the method of constant stimuli.
• Sketch a typical psychometric function from such an experiment and explain what it means.
• Explain what a difference threshold (jnd) is and give some examples.
• Write out the equation for Weber's law and explain it.
• Use Weber's law to figure out the jnd for a stimulus with a given intensity.
• Explain what psychophysical scaling is.
• Describe how a researcher might discover a psychophysical function using the method of direct magnitude estimation.
• Sketch some typical psychophysical functions.
• Write out the equation for Stevens's power law and explain it.
• Explain how dimensions for which the exponent is positive differ from those for which it is negative.
• Explain adaptation level theory and give some examples.
• Argue in support of the statement, "What we perceive is not the same as what is out there."

Relevant Concepts

What to Know: Part II

Can You Do These Things?

• Draw and label a diagram of the human eye.
• Explain the function of each major anatomical structure in the eye.
• Explain what accomodation is, how it works, and give some examples.
• Explain why some people are myopic or hypermetropic.
• Draw and label a diagram of the layers of the human retina.
• Describe the process of transduction in the retina.
• Describe the major characteristics of rod and cone receptors (e.g., sensitivity, etc.).
• Diagram and describe the distribution of rod and cone cells on the retina.
• Give some examples of how the major characteristics of rods and cones-along with their distribution-explain everyday perceptual phenomena.
• Describe the blind spot.
• Describe the difference between parvo and magno ganglion cells.
• Diagram the path(s) of information through the geniculostriate system.
• Distinguish the "what" and "where" systems.
• Describe the effects of damage to various areas of the visual system.
• Explain what a retinotopic (or topographic) map is, and how this concept is relevant to the LGN and visual cortex.
• Describe how, in general, the receptive fields of visual neurons change as one moves further along the visual pathways.
• Describe the functions of the different areas of the visual cortex.

Relevant Concepts

What to Know: Part III

Can You Do These Things?

• Describe, in general, the relationship between light intensity and perceived brightness, and sketch a psychophysical function for this relationship.
• Sketch a typical dark adaptation curve and explain what it means.
• Describe the role of both rods and cones in dark adaptation.
• Explain how convergence accounts for the greater sensitivity of rods.
• Describe how the Snellen and Landhold tests are used to determine visual acuity.
• Explain how convergence accounts for the greater acuity of cones.
• Define simultaneous brightness contrast and sketch a stimulus that demonstrates it.
• Explain how lateral inhibition accounts for simultaneous brightness contrast.
• Explain what is interesting about Figure 4-20 (p. 113) in the textbook, and how this relates to the concept of top-down processing

Relevant Concepts

What to Know: Part IV

Can You Do These Things?

• Describe the relationship of visible light to the electromagnetic spectrum.
• Describe the general relationship between light wavelength and color perception.
• Describe "Newton's experiment" and what it showed.
• Explain why Newton's experiment works.
• Explain what Newton meant when he said that the light rays "are not coloured." (Or, for that matter, what I mean when I say that a tree that falls in the forest without anyone around to hear it does not make a sound."
• Distinguish hue, saturation, and brightness.
• Describe what happens in a color matching experiment.
• Distinguish additive from subtractive color mixing.
• Explain why mixing blue and yellow paint makes green paint, but mixing blue and yellow light makes white light.
• Summarize the trichromatic theory of color vision.
• Use Figure 5-14 (p. 136) to determine the relative activation level of blue, green, and red cones in response to a light of a particular wavelength.
• Use Figure 5-14 to determine the color that someone perceives given a particular level of activation of that person's blue, green, and red cones.
• Explain what is wrong with a person who is color blind (both protanopia and deuteranopia).
• Summarize the opponent-process theory of color vision.
• Explain how the opponent-process theory accounts for color afterimages.

Relevant Concepts