CHAPTER 1

Understanding Animal Behavior

The subject of this book is animal behavior. What is animal behavior, and whatdoes it mean to understand animal behavior? As we shall see in this chapter, thereare several answers to these questions, depending on research tradition and whatone intends to understand. At the same time, different theories of behavior havemuch the same scope:

• They deal with how the animal as a whole interacts with its physical, ecologicaland social environment, in particular through reception of sensory stimulationand behavioral actions such as motor patterns, pheromone release, changein body coloration and so forth.

• They want to explain, predict or control what animals do.

• They consider situations in which internal factors such as memory and physiologicalstates are not easily accessible.

Besides our theoretical interests, there are great practical demands for knowledgeof behavior. People who work with animals, such as zookeepers, farmers, animaltrainers, veterinarians and conservationists, constantly need such knowledge.

Ethology and comparative psychology are two major research traditions dealingwith behavior. Within these disciplines, it has been and still is important to explorebehavior as a function of external stimuli and readily observable factors suchas species, age and sex. Internal factors such as physiological states and memory,on the other hand, are studied indirectly or inferred from observations of behavior,history of events and the passage of time. The reason for this difference is that inalmost all situations in which we encounter animal behavior, it is relatively easy tomonitor and control the external situation and to record behavior, but the access tointernal factors is usually limited. However, ignoring internal factors undoubtedlyhas shortcomings. First, it is clear that external factors are not alone in causingbehavior. An animal can react quite differently to the same piece of food, e.g., dependingon hunger and memory of experiences with similar food items. Second, itis difficult to reconstruct behavior mechanisms from pure observations of behavior,and physiological knowledge about internal mechanisms may greatly facilitate thedevelopment of behavior models.

But what is the proper compromise between the complexity of nervous systemand body physiology and the need for understanding at the behavioral level? Therole of internal factors in models of behavior has been and still is a matter of muchdiscussion. The most famous of these debates is the confrontation between behaviorists,who attempted to avoid internal factors altogether, and cognitive psychologists,who instead encouraged theorizing about internal processes (Leahey2004; Skinner 1985; Staddon 2001; see Section 1.3.5). We will discuss this issueat length in Chapter 6. In short, our position is that internal factors are vital forunderstanding behavior, but at the same time we side with behaviorists (and, ofcourse, ethologists) in their focus on behavior and regard their contribution to theunderstanding of behavior as very significant.

In this chapter we first consider the different kinds of explanations that have beenconsidered for behavior. We then introduce the reader to major theories of behavior,focusing on their structure and the causal factors invoked to explain behavior.Finally, we introduce neural networks models, which we will explore in this bookas a potential framework for understanding behavior.

1.1 THE CAUSES OF BEHAVIOR

In biology, two types of causal explanations are generally recognized: proximateand ultimate explanations (Baker 1938; Mayr 1961). Proximate explanations appealto motivational variables, experiences and genotype as the cause of behavior.Ultimate explanations refer to selection pressures and other factors that cause theevolution of behavior. These two kinds of causal explanations are independent andcomplementary, serving different purposes: one cannot replace the other. To clarifythis concept, Lorenz (1981; §1.6) offers the following example. The ultimatecause of cars is, of course, traveling. If the engine breaks, however, the ultimatecause cannot start it again: we need to know how the engine works (proximatecauses). Figure 1.1 gives another example of this distinction, in the context of behavior.

Note that, in principle, we can learn independently about proximate andultimate causes. However, the two are also related (since behavior is a result ofevolution and influences evolution), and we probably will learn faster about one byalso considering the other.

A more detailed set of explanations was suggested Niko Tinbergen in definingthe scope of ethology (Tinbergen 1963). Rather than distinguishing just betweenproximate and ultimate causes, he argued that four questions must be answered tounderstand behavior. These are usually summarized as follows:

1. What causes a behavior to appear at a given moment and how does the behavioralmachinery work?

2. How does behavior develop during an individual's lifetime?

3. What is the evolutionary history of the behavior?

4. How does the behavior contribute to survival and reproduction?

The first two questions are about the proximate explanation. Splitting it in two allowsus to study behavior mechanisms at one time separately from how they changewith time, an advantage on which we will capitalize. Tinbergen's third questionaims at a description of evolutionary change and does not refer to any causal explanation.The fourth question, as it is expressed, does not strictly refer to a causalexplanation but to so-called final or functional explanations. These, with a leap oflogic, invoke the effects of a behavior (contribution to survival and reproduction)as the cause of the behavior itself. In practice, however, the fourth question oftencovers true causal studies of the outcome of evolution, i.e., studies of how naturalselection and other factors can modify behavior in an evolving population. Additionaldiscussion of explanations of animal behavior can be found in Alcock andSherman (1994), Dewsbury (1992, 1999), and Hogan (1994a). In this book weconsider three kinds of causal explanations closely related to Tinbergen's:

1. Motivation

2. Ontogeny

3. Evolution

To us, understanding behavior means having answers to all of these questions, andthis book is organized after this classification. The three...