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 in science and beyond. Within North American psychology it was the dominant school of thought for several decades. Behaviorist theory also affected education practice, particularly with Watson’s book Psychological Care of Infant and Child (1928). Watson once made the famous statement:
Give me a dozen healthy infants, well-formed, and my own specified world to bring them up in and I’ll guarantee to take any one at random and train him to become any type of specialist I might select—doctor, lawyer, artist, merchant-chief, and, yes, even beggarman and thief, regardless of his talents, penchants, tendencies, abilities, vocations, and race of his ancestors.
This epitomizes behaviorist ideas about child rearing. Watson considered the upbringing of children to be an objective, almost scientific exercise, without the need for affection or sentimentality.
Watson’s most famous student was Burrhus Frederic Skinner (1904–1990), who applied behaviorist ideas to the study of learning. For Skinner (1938) and his behaviorist colleagues, learning had to do with changing relationships between visible entities, not with what might be going on inside the animal’s head. In particular, behaviorist learning theorists suggest that learning refers to changes in the frequency of responding due to its consequences. Most of their experiments involve operant conditioning (see Chapter 8), in which a certain response by the animal (e.g., pressing a lever) is rewarded (“reinforced”) with food.
Cognitive psychology
Within experimental psychology there came a reaction to behaviorism in what we now call cognitive psychology. In contrast to behaviorism, cognitive psychologists start with the assumption that individuals (humans and other animals) have a mental life that can be investigated (Chapter 9). For instance, Skinner (1957) maintained that language development in children was a learning process, in which responses (i.e., uttering certain sounds) were reinforced. The American linguist Noam Chomsky (1959) wrote a highly critical review of Skinner’s book on language development, suggesting that language acquisition is not a case of instrumental conditioning, but a much more complex interaction between experience and internal cognitive mechanisms (Chapter 7). At birth the child is already endowed with essential knowledge of language, the theory of which is known as Universal Grammar. Clearly, learning is involved in the development of language, but it is not the only factor. Chomsky and colleagues have recently described the growth of language in the child as “the interplay of three factors: domain-specific principles of language (Universal Grammar), external experience, and properties of non-linguistic domains of cognition including general learning mechanisms and principles of efficient computation” (Yang et al. 2017). Another important publication that signaled the beginning of the cognitive revolution is a book by the British psychologist Donald Broadbent (1958) who, in contrast to Skinner, analyzed learning and memory in terms of cognitive mechanisms rather than stimulus–response relations. Hogan (1988, 2017) has noted that what cognitive psychologists call “cognitive structures” are in fact the same as the causal mechanisms that were proposed by ethologists such as Lorenz and Tinbergen (Chapters 3 and 9).
Four Questions in the Study of Animal Behavior
Niko Tinbergen published a very important paper in 1963, in which he outlined four major questions in the study of animal behavior, namely causation, development, survival value, and evolution. As he readily admitted, Tinbergen wasn’t original, because three of these questions (causation, survival value, and evolution) had already been put forward by the British biologist Julian Huxley (1887–1975) as the major questions in biology, but Tinbergen added a fourth question, development. Many authors, including ourselves, use the word function as a substitute word for survival value, but the term function is used in many different ways in biology (Wouters 2003), and care is necessary when using it. It should also be mentioned that the evolutionary biologist Ernst Mayr (1904–2005) in 1961 popularized a different categorization of problems in biology: proximate and ultimate causation. Proximate causation is similar to Tinbergen’s causal question, but ultimate causation is a controversial term that deals with evolutionary issues somewhat differently from Tinbergen’s questions of survival value and evolution. However, no matter how these questions are broken up, it is crucially important that students of animal behavior be quite clear about the type of question they are addressing when they study or speak of animal behavior.
We find Tinbergen’s analysis so important that we would say you cannot really understand animal behavior if you do not also understand the meaning of his four questions. Some of the more heated contemporary debates in the field of animal behavior can often be traced to misunderstandings about the meaning of these questions (e.g., Hogan 1994, 2017; Bolhuis & Macphail 2002). It is essential, therefore, that any productive discussion about animal behavior involves participants that are capable of clearly stating which of the four questions they are addressing. This view of animal behavior has also served as the framework for the organization of the present book, with the first half covering mostly causal and developmental topics while the second half deals with questions of survival value (or function) and evolution.
Tinbergen’s four questions are sometimes also called the four whys, because they represent four ways of asking “why does this animal behave in this way?” Let’s consider a bird singing at dawn, say a male song sparrow (Melospiza melodia). The question is: why is this bird singing? This seems a perfectly straightforward question, but in fact it is not, because answers can take any of four different forms. These different forms—you’ve guessed it—have to do with Tinbergen’s four questions. The first question concerns causation: what causes the bird to sing? The answers include the stimuli or triggers of behavior whether they be internal or external, the way in which behavioral output is guided, factors that stop behavior, and the like. These are questions concerning the causation of behavior. Sometimes this is called motivation, a topic discussed at length in Chapter 3. Tinbergen’s question of causation also concerns the mechanisms or structure of behavior. These mechanisms involve the “machinery” that operates within the animal and which are responsible for the production of behavioral output (Chapters 5 and 9).
The second question is about development: How did the singing behavior of the bird come about in the lifetime of an animal? A male song sparrow does not sing immediately after it has hatched from the egg, and it takes quite some time before it has developed a song, a process that involves learning. Such questions that concern development of behavior, sometimes also called ontogeny, will be discussed explicitly in Chapter 7. The third question has to do with the consequences of singing for the singer’s fitness: What is the function of the bird singing; what is it