CHAPTER 2
Motivation
BILL P. GODSIL, MATTHEW R. TINSLEY, AND MICHAEL S. FANSELOW
33Why Do Theories of Behavior Need Motivational
Constructs? 33
A Definitional Framework for Motivation 34
Impetus for the Development of Functional Behavior
Systems 34
What Is Motivation? 35
FEEDING 35
Factors Governing Initiation of Feeding Behavior 36
Factors Governing Variety of Intake 37
Factors Governing the Incentive Aspects of Foods 38
Feeding Response Organization 39
A Feeding Response Organization: The Predatory Behavior
System of the Rat 40
FEAR MOTIVATION 41
The Pervasiveness of Fear in Motivated Behavior 42
Factors Governing Initiation of Fear 42
Functional Behavior Systems Analysis of Defensive
Behavior 44
The Organization of Defensive Behavior: Predatory
Imminence Theory 45
Defensive Behaviors on the Predatory Imminence
Continuum 45
Neural Substrates of Learned Defensive Behavior 47
Neural Substrates of Unlearned Defensive Behavior 48
SEXUAL MOTIVATION 48
Cues That Signal Reproductive Opportunity 49
Organization of the Sexual Behavior System 50
TEMPERATURE MOTIVATION 51
Thermoregulatory Responses 51
Learning and Thermoregulatory Responses 53
A Thermoregulatory Behavior System? 53
CONCLUSIONS 54
REFERENCES 55The first two questions that a chapter on motivation must
confront may betray the current status of motivational con-
structs in much of psychology. The first is, Why do we need
motivational concepts to explain behavior? The second is,
How do we define motivation? The first goal of this chapter
is to answer these questions in a general way by providing
a framework with which to analyze basic motivational
processes. We then apply this general framework to four mo-
tivated behavior systems: feeding, fear, sexual behavior, and
temperature regulation. By so doing, we hope to illustrate the
power of current thinking about motivation as an organizing
and predictive structure for understanding behavior.
Why Do Theories of Behavior Need
Motivational Constructs?The goal of psychological theories is to explain and predict
the variance in behavior. The two global factors to which
this variance is most often attributed are genetic and learned
influences. For instance, a particular species is genetically
programmed to use certain sources of nourishment and not
others. It is also clear that humans and other animals learn
that some edible stimuli contain vital nutrients and others are
toxic. Even complete knowledge of these factors and how
they interact is probably not sufficient to understand all be-
havior; some variance is left over. Motivational constructs
are invoked to explain this leftover variance. Genetically, hu-
mans need certain lipids, proteins, sugars, and vitamins to
become reproductive individuals. We learn how to procure
these commodities from our environment. Yet an individual
may not always consume the perfect food when it is avail-
able, while at other times such food may be consumed toThe authors would like to thank Polar Bears Alive of Baton Rouge,
LA, for the use of the polar bear photo. The authors would also like
to thank M. Domjan for the quail photo, K. Hollis for the pictures of
the fish, and S. Crowley for the pictures of the rats.