than it did initially. Gone are the days when one author could write a textbook both comprehensive and authoritative: Robert Hinde’s classic Animal Behaviour: A Synthesis of Ethology and Comparative Psychology (1970) is an outstanding example of such a book, and it continues to inspire many of us. Given the breadth of contemporary animal behavior research, we felt that it was important to invite experts in the respective subdisciplines to write a chapter about their specialist topic.
Second, a large proportion of extant textbooks are single-author volumes that approach animal behavior from a particular perspective, for example from an evolutionary point of view or with the emphasis on mechanisms. We believe that a modern science of animal behavior should encompass both functional and causal approaches. For such a comprehensive approach, we found the classic formulation of the aims and methods of ethology (the study of animal behavior) by Niko Tinbergen, one of its founding fathers, most useful. Tinbergen suggested that there are four basic questions in animal behavior, namely about causation, development, survival value (function), and evolution. We agree with Tinbergen that all these four questions are equally important. Hence all of them are represented in this book. Like Tinbergen, we also find it important to distinguish among the four questions. In particular, it is important to realize which of the four questions is addressed, and to use a research approach appropriate for that question. Most chapters in the book focus on one of the four questions, with cause and development being the main subjects of the first ten chapters, and survival value (function) and evolution being the main subjects of the last seven chapters. But most chapters are also concerned with more than one question, noted separately of course, supporting Tinbergen’s claim that all questions should be answered.
We are very pleased with the enthusiastic response we received from the authors invited to contribute to this book. They are all leaders in their respective fields, and we feel privileged that they participated in this project. Robert Hinde has passed away since his foreword was written, but his words are just as relevant to the second edition of this book as they were to the first. His influence remains.
1 the study of animal behavior
JOHAN J. BOLHUIS, LUC-ALAIN GIRALDEAU AND JERRY A. HOGAN
INTRODUCTION
The scientific study of animal behavior is often called ethology, a term used first by the nineteenth century French zoologist Isidore Geoffroy Saint Hilaire, but then used with its modern meaning by the American zoologist Wheeler (1902). Ethology is derived from the Greek ethos, meaning “character.” The word “ethics” is also derived from the same Greek word, which makes sense, because ethics is basically about how humans ought to behave. Unfortunately, the word “ethology” is also often confused with the word “ethnology” (the study of human peoples), with which it has nothing in common. In fact, the very word processor with which we are writing this chapter keeps prompting us to replace “ethology” by “ethnology”! For whatever the reason, the word “ethology” is not used as much as it used to be, although there is still an active animal behavior journal bearing this name. Instead of “ethology,” many authors now use the words “animal behavior” or “behavioral biology” when they refer to the scientific study of animal behavior.
A Brief History of Behavioral Biology
Early days
Scientists (and amateurs) have studied animal behavior long before the word “ethology” was introduced. For instance, Aristotle had many interesting observations concerning animal behavior. The study of animal behavior was taken up more systematically, however, mainly by German and British zoologists around the turn of the nineteenth century. The great British naturalist Charles Darwin (1809–1882), in his classic book on the theory of evolution by natural selection (1859), devoted a whole chapter to what he called “instinct.” As early as 1873, a British amateur investigator, Douglas Spalding, recorded some very interesting observations on the instinctive behavior of young domestic chicks, including a phenomenon that was later called “imprinting” (Chapter 7). At the beginning of the twentieth century, the behavior of animals was also studied in the context of learning by the Russian physiologist Ivan P. Pavlov (1927) and the American psychologist Edward L. Thorndike (1911; Chapter 8).
Lorenz and Tinbergen
In the middle of the twentieth century, the study of animal behavior became an independent scientific discipline, called ethology, mainly through the efforts of two biologists, the Austrian Konrad Lorenz (1903–1989) and the Dutchman Niko Tinbergen (1907–1988). It can be said that Lorenz was the more philosophical and theoretical of the two. He put forward a number of theoretical models on different aspects of animal behavior such as evolution and motivation. He was also the more outspoken of the two men, and some of his publications met with considerable controversy. Tinbergen was very much an experimentalist, who together with his students and collaborators conducted an extensive series of field and laboratory experiments on the behavior of animals of many different species. In 1973, Lorenz and Tinbergen were awarded the Nobel Prize for Physiology and Medicine. They shared their prize with Karl von Frisch (1886–1982), an Austrian comparative physiologist and ethologist who had pioneered research into the dance “language” of bees (Chapter 14).
Ethology and comparative psychology
During the early days of ethology there was a certain amount of scientific rivalry between mainly European ethologists and North American experimental psychologists, who also studied animal behavior in what was usually called comparative psychology. The European ethologists emphasized that animal behavior is a biological phenomenon, and as such a product of evolution. This is exemplified by the use of the word “instinct” (e.g., in the title of Tinbergen’s 1951 classic book The Study of Instinct), which referred to the “innate” components of behavior that are subject to natural selection. A prominent critique of this way of thinking came from the American psychologist Daniel Lehrman, in his 1953 paper “A critique of Konrad Lorenz’ theory of instinctive behavior.” In this paper he argued against Lorenz’ theory in which behavior can be dissected into “innate” and “acquired” (learned) components (see Chapter 7 for a more detailed discussion of these issues). In general, American psychologists emphasized the effects of learning on behavior. Pavlov had already demonstrated the importance of what we now call Pavlovian (or classical) conditioning, and Thorndike studied learning processes that are now known as instrumental conditioning (Chapter 8). Another difference between the ethologists and experimental psychologists was that the former often observed animals of many different species in their natural environment, while the latter, despite the name comparative psychology, often concentrated on one species, such as the rat or the pigeon, that was studied exclusively in the laboratory.
Behaviorism
The emphasis of the North American psychologists on learning was epitomized by the rise of behaviorism in the 1930s. Behaviorism was a very influential school of thought initiated by the American psychologist John B. Watson (1878–1958), with his book Behaviorism (1924). Essentially, Watson considered psychological phenomena to be physical activity rather than some kind of mental event. He proposed that we cannot make any scientific statements about what might be going on in our minds, and that introspection was unreliable. Rather, for behaviorists, psychology is the study of observable behavior and of the external physical factors that influence it. At the time, behaviorism was extremely influential
