Other early ethologists, such asEugène Marais,Charles O. Whitman,Oskar Heinroth,Wallace Craig andJulian Huxley, instead concentrated on behaviours that can be calledinstinctive in that they occur in all members of a species under specified circumstances.[4][5][2] Their starting point for studying the behaviour of a new species was to construct anethogram, a description of the main types of behaviour with their frequencies of occurrence. This provided an objective, cumulative database of behaviour.[2]
In 1972, the English ethologist John H. Crook distinguished comparative ethology from social ethology, and argued that much of the ethology that had existed so far was really comparative ethology—examining animals as individuals—whereas, in the future, ethologists would need to concentrate on the behaviour of social groups of animals and the social structure within them.[9]
E. O. Wilson's bookSociobiology: The New Synthesis appeared in 1975,[10] and since that time, the study of behaviour has been much more concerned with social aspects. It has been driven by the Darwinism associated with Wilson,Robert Trivers, andW. D. Hamilton. The related development ofbehavioural ecology has helped transform ethology.[11] Furthermore, a substantial rapprochement withcomparative psychology has occurred, so the modern scientific study of behaviour offers a spectrum of approaches. In 2020, Tobias Starzak and Albert Newen from the Institute of Philosophy II at theRuhr University Bochum postulated that animals may have beliefs.[12]
Tinbergen argued that ethology needed to include four kinds of explanation in any instance of behaviour:[13][14]
Function – How does the behaviour affect the animal's chances of survival and reproduction? Why does the animal respond that way instead of some other way?
Causation – What are the stimuli that elicit the response, and how has it been modified by recent learning?
Development – How does the behaviour change with age, and what early experiences are necessary for the animal to display the behaviour?
Evolutionary history – How does the behaviour compare with similar behaviour in related species, and how might it have begun through the process ofphylogeny?
These explanations are complementary rather than mutually exclusive—all instances of behaviour require an explanation at each of these four levels. For example, the function of eating is to acquire nutrients (which ultimately aids survival and reproduction), but the immediate cause of eating is hunger (causation). Hunger and eating are evolutionarily ancient and are found in many species (evolutionary history), and develop early within an organism's lifespan (development). It is easy to confuse such questions—for example, to argue that people eat because they are hungry and not to acquire nutrients—without realizing that the reason people experience hunger is because it causes them to acquire nutrients.[15]
^Bateson, Patrick (1991).The Development and Integration of Behaviour: Essays in Honour of Robert Hinde. Cambridge University Press. p. 479.ISBN978-0-521-40709-0.
^"The Nobel Prize in Physiology or Medicine 1973".Nobelprize.org. Retrieved9 September 2016.The Nobel Prize in Physiology or Medicine 1973 was awarded jointly to Karl von Frisch, Konrad Lorenz and Nikolaas Tinbergen 'for their discoveries concerning organization and elicitation of individual and social behaviour patterns'.
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