Chapter 4 Introduction

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To survive, animals must adapt to their environments. Evolution by natural selection, which we discussed in Chapter 3, is the slow, long-term adaptive process that equips each species for life within a certain range of environmental conditions. But the environment is never constant; it changes from place to place and from time to time, and individuals must adapt to these changes over their lifetimes. To be efficient in finding foods, finding mates, avoiding predators, and carrying out the other necessities of survival and reproduction, animals must adjust to the ever-changing conditions of the specific environments in which they live. In other words, they must learn.

The term learning is used in various ways by different psychologists to refer to a wide variety of phenomena. For our purposes, we can define it broadly as any process through which experience at one time can alter an individual’s behavior at a future time. Experience in this definition refers to any effects of the environment that are mediated by the individual’s sensory systems (vision, hearing, touch, and so on). Behavior at a future time refers to any subsequent behavior that is not part of the individual’s immediate response to the sensory stimulation during the learning experience. If I make a clicking sound just before flashing a bright light into your eyes, your immediate response to the click or to the light (such as blinking) does not exemplify learning. But your increased tendency to blink to the click alone, the next time I present that sound, does exemplify learning.

Most of psychology is in one way or another concerned with the effects of experience on subsequent behavior. For example, social psychologists try to explain people’s beliefs and social behaviors in terms of their past experiences, clinical psychologists try to explain people’s emotional problems in such terms, and cognitive psychologists try to understand the basic mental processes that are involved in people’s ability to learn. Thus, most chapters in this book, or in any other introduction to psychology, are about learning in one way or another.

Note that this chapter is in the part of the book that links human psychology to the psychology of animals in general. From an evolutionary perspective, learning is a very ancient set of abilities. All animals that have any kind of nervous system have acquired, through natural selection, some abilities to learn. We humans are in some ways unique but in many ways similar to other species in our basic mechanisms of learning.

We begin this chapter with discussions of two very general varieties of learning: classical conditioning and operant conditioning. Then, we’ll turn to discussions of the roles of play, exploration, and observation in learning; and finally, we will look at some very specialized forms of learning, such as learning what foods are good or bad to eat.