Deck 4: Section 1 : Sensation and Perception

Question 1

Why is it incorrect to say that color is a property of an object? Describe how three cone types allow us to perceive color.

Answer 1

The answer should provide the following information: (1) Sir Isaac Newton pointed out that color was not something "in" light. Nor is it "in" the object. An apple is not red. Rather, color is our perceptual response to different wavelengths of light. We perceive an apple to be red because it reflects light waves of a particular frequency; (2) Humans have specialized cones to detect short wavelengths (S-cones), medium wavelengths (M-cones) and long wavelengths (L-cones). Activation of these cones corresponds to our perception of bluish, greenish, and reddish colors, respectively; (3) Depending on the pattern of firing among these three types of cones, all of the shades of color in the visual spectrum can be perceived.

Question 2

What are the three properties of sound waves? How is each of these properties perceived?

Answer 2

The answer should indicate that the three properties of sound waves are frequency, amplitude, and complexity. The frequency of a sound wave, or its wavelength, depends on how often the peak in air pressure passes the ear. Changes in the physical frequency of a sound wave are perceived by humans as changes in pitch. The amplitude of a sound wave refers to its height relative to the threshold for human hearing. Amplitude corresponds to loudness, or sound intensity. Differences in the complexity of sound waves or their mixing of frequencies correspond to timbre, a listener's experience of sound quality or resonance.

Question 3

Discuss how the "just noticeable difference" and Weber's law help explain how we detect changes in stimulation.

Answer 3

The answer should indicate that the smallest change in stimulation that a person can detect is the just noticeable difference. It is not a fixed quantity; instead, it depends on how intense the stimuli being measured are and on the particular sense being measured. It can be calculated for each sense and is roughly proportional to the magnitude of the standard stimulus. Weber's law states that the just noticeable difference of a stimulus is a constant proportion despite variations in intensity. For example, to notice a change in weight, the change must be about 2 to 3 percent. It is easy to notice the difference between 1 and 2 pounds, but impossible to notice the difference between 100 and 101 pounds.

Question 4

Although you have never seen a cherry-red spider, you have no problem detecting that one is currently crawling across your floor. Using this example, describe the processes of sensation and perception of visual stimuli. With respect to perception, describe the brain structures and functions, as well as cognitive processes if applicable, underlying color identification, object identification, and movement.

Question 5

Distinguish between image-based and parts-based theories of object recognition, citing evidence for and against each theory.

Question 6

What are the types of touch receptors located under the skin's surface? Describe how touch is represented in the brain.

Question 7

Discuss how signal detection theory represents an advance from earlier research on thresholds, and explain how a person's decision criterion contributes to the detection of a stimulus.

Question 8

Compare and contrast the two chemical senses of smell and taste. Include (a) a discussion of the sensory receptors for smell and taste and (b) a discussion of the pathways by which smell and taste sensations are transmitted.

Question 9

Describe each of the six basic perceptual principles of Gestalt psychology.

Question 10

You are drawing an outdoor scene, including trees, flowers, shrubbery, and buildings near and far from your position at your easel. Describe how you would use at least four monocular cues to indicate depth and dimension in your drawing.

Question 11

What are the three properties of light waves? How is each of these properties perceived?

Question 12

Describe the process by which the lens changes shape to focus images on the retina, and briefly illustrate two common problems associated with this phenomenon: myopia and hyperopia.

Question 13

Describe the flow of visual information from the eye to the primary visual cortex. Then describe the neural systems for perceiving shape, identifying what an object is, and identifying where an object is located in space and how it can be utilized.

Question 14

Describe the three major structures and functions of the outer, middle, and inner ear.

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