REVIEW Basic Concepts of Sensation and Perception

Learning Objectives

Test Yourself by taking a moment to answer each of these Learning Objective Questions (repeated here from within the module). Research suggests that trying to answer these questions on your own will improve your long-term memory of the concepts (McDaniel et al., 2009).

Question

16-1 What are sensation and perception? What do we mean by bottom-up processing and top-down processing?

ANSWER: Sensation is the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment. Perception is the process of organizing and interpreting this information, enabling recognition of meaningful events. Sensation and perception are actually parts of one continuous process. Bottom-up processing is sensory analysis that begins at the entry level, with information flowing from the sensory receptors to the brain. Top-down processing is information processing guided by high-level mental processes, as when we construct perceptions by filtering information through our experience and expectations.

Question

16-2 What three steps are basic to all our sensory systems?

ANSWER: Our senses (1) receive sensory stimulation (often using specialized receptor cells); (2) transform that stimulation into neural impulses; and (3) deliver the neural information to the brain. Transduction is the process of converting one form of energy into another.

Question

16-3 How do absolute thresholds and difference thresholds differ, and what effect, if any, do stimuli below the absolute threshold have on us?

ANSWER: Our absolute threshold for any stimulus is the minimum stimulation necessary for us to be consciously aware of it 50 percent of the time. Signal detection theory predicts how and when we will detect a faint stimulus amid background noise. Individual absolute thresholds vary, depending on the strength of the signal and also on our experience, expectations, motivation, and alertness. Our difference threshold (also called just noticeable difference, or jnd) is the difference we can discern between two stimuli 50 percent of the time. Weber's law states that two stimuli must differ by a constant minimum percentage (not a constant amount) to be perceived as different. Priming shows that we process some information from stimuli below our absolute threshold for conscious awareness.

Question

16-4 Does subliminal sensation enable subliminal persuasion?

ANSWER: Subliminal stimuli are those that are too weak to detect 50 percent of the time. While subliminal sensation is a fact, such sensations are too fleeting to enable exploitation with subliminal messages: There is no powerful, enduring effect.

Question

16-5 What is the function of sensory adaptation?

ANSWER: Sensory adaptation (our diminished sensitivity to constant or routine odors, sounds, and touches) focuses our attention on informative changes in our environment.

Question

16-6 How do our expectations, contexts, motivation, and emotions influence our perceptions?

ANSWER: Perceptual set is a mental predisposition that functions as a lens through which we perceive the world. Our learned concepts (schemas) prime us to organize and interpret ambiguous stimuli in certain ways. Our physical and emotional context, as well as our motivation, can create expectations and color our interpretation of events and behaviors.

Terms and Concepts to Remember

Test yourself on these terms.

Question

sensation (p. 200)
perception (p. 200)
bottom-up processing (p. 200)
top-down processing (p. 200)
transduction (p. 200)
absolute threshold (p. 201)
signal detection theory (p. 201)
subliminal (p. 201)
priming (p. 201)
difference threshold (p. 202)
Weber's law (p. 203)
sensory adaptation (p. 204)
perceptual set (p. 205)
the minimum stimulus energy needed to detect a particular stimulus 50 percent of the time.
information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations.
the activation, often unconsciously, of certain associations, thus predisposing one's perception, memory, or response.
the process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment.
analysis that begins with the sensory receptors and works up to the brain's integration of sensory information.
diminished sensitivity as a consequence of constant stimulation.
conversion of one form of energy into another. In sensation, the transforming of stimulus energies, such as sights, sounds, and smells, into neural impulses our brain can interpret.
a theory predicting how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise). Assumes there is no single absolute threshold and that detection depends partly on a person's experience, expectations, motivation, and alertness.
the minimum difference between two stimuli required for detection 50 percent of the time. We experience the difference threshold as a just noticeable difference (or jnd).
a mental predisposition to perceive one thing and not another.
the principle that, to be perceived as different, two stimuli must differ by a constant minimum percentage (rather than a constant amount).
the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events.
below one's absolute threshold for conscious awareness.

Experience the Testing Effect

Test yourself repeatedly throughout your studies. This will not only help you figure out what you know and don’t know; the testing itself will help you learn and remember the information more effectively thanks to the testing effect.

Question 6.1

1. Sensation is to ________ as perception is to ________.

A.
B.
C.
D.

Question 6.2

2. The process by which we organize and interpret sensory information is called .

Page 209

Question 6.3

3. Subliminal stimuli are

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B.
C.
D.

Question 6.4

4. Another term for difference threshold is the .

Question 6.5

5. Weber's law states that for a difference to be perceived, two stimuli must differ by

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B.
C.
D.

Question 6.6

6. Sensory adaptation helps us focus on

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B.
C.
D.

Question 6.7

7. Our perceptual set influences what we perceive. This mental tendency reflects our

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B.
C.
D.

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