Objectives
After completing this chapter, you will be able to- differentiate among sensation, perception, and cognition;
- describe key aspects of the visual process;
- explain the trichromatic theory of color perception;
- describe key aspects of the hearing process;
- identify principal features of the processes associated with taste, the skin senses,
smell, kinesthesis, and the vestibular sense.
A whole industry can sometimes be based on a single sense. The early motion
picture industry appealed primarily to vision. Radio appeals primarily to hearing.
Today’s motion pictures and television make a combined appeal to vision and
hearing. Other senses such as taste and smell play important roles in the food
industry and the perfume industry.
It is difficult to overestimate the importance of the senses. They are our gate-
ways to experience. Without our senses we would be creatures living in solitary
confinement. We wouldn’t know the world “out there,” the world beyond the
self. Learning would be impossible because, as you will see in chapter 6, the very
definition of learning requires that we be capable of experience. Consequently,
psychology considers it important to study the process of sensation, the basic
process by which we obtain information about external reality.
Here is a useful way to think about the character of conscious experience.
Imagine three ascending steps. The first step is associated with sensation.Sensa-
tion refers to the raw data of experience. Seeing a flash of light, hearing a single
note sounded on a musical instrument, or feeling the touch of a fingertip, are all
examples of simple sensations. Instead of yourself, imagine that an infant only a
few days old is having these sensations. To the extent that they have little organi-
zation and little meaning, they are close to simple sensations.
The second step is associated with perception.Perception refers to organized
experience. If a set of notes sounded on a musical instrument takes on a particu-
lar form, and you hear a melody, you have attained the level of perception. Per-
ception is explored in chapter 5.
The third step is associated with cognition.Cognition refers to knowing.
Thinking and concept formation are processes associated with cognition. If you
perceive a melody and remember the name of the song, you have attained the
level of cognition. You know what you’re listening to. (Note that the familiar
word recognitioncan be broken down into “re” and “cognition,” suggesting that its
root meaning is to “know again.”) Cognition is explored in chapter 9.46 PSYCHOLOGY