Ethology
Ethology is a branch of zoology concerned with the study of animal behavior. Ethologists study a range of animal behaviors including sexual selection, social behavior, kinship, reciprocity and cooperation, parental investment, conflict and aggression.
Methodologically, ethologists engage in a tradition of hypothesis-driven experimental investigation, often in the field. This combination of lab work with field study reflects an important underpinning of the discipline: behavior is assumed to be adaptive to the species’ natural environment.
Ethology emerged as a discipline in the 1920s; its founding practitioners were Konrad Lorenz, Karl von Frisch, and Niko Tinbergen, who were jointly awarded the 1972 Nobel Prize in Physiology for their contributions to the study of behavior.
One of the key ideas of classical ethology, attributed to Karl Lorenz but likely influenced by the German ornitholoist Oscar Heinroch, was the concept of fixed action patterns (FAPs). FAPs are instinctive responses that would occur reliably in the presence of identifiable stimuli (called sign stimuli or releasing stimuli). (for example, goose)
Classical ethology spawned problematic grand theories about internal control mechanisms and the extent to which they were genetically hardwired (innate or instinctive, according to the terminology). (what do we think today that's different?)
Although ethology as a disciplinary label has largely faded from use, the desire to understand the animal world has made its intellectual inheritors – such as behavioral ecology and evolutionary psychology – rapidly growing fields. (today the focus is on xyz, but retains ethology’s tradition of abc)
Relation to comparative psychology
A comparison of classical ethology to early work in comparative psychology, an alternative approach to animal behavior helps to illuminate the methodological and conceptual underpinnings of both:
- As opposed to ethology, comparative psychology construes its study as a branch of psychology rather than as one of biology. Thus, where comparative psychology sees the study of animal behavior in the context of what is known about human psychology, ethology situates the study of animal behavior in the context of what is known about animal anatomy, physiology, neurobiology, and phylogenetic history.
- Early comparative psychologists concentrated on gaining extensive knowledge of the behavior of very few species, while ethologists were more interested in gaining knowledge of behavior in a wide range of species in order to be able to make principled comparisons across taxonomic groups. Comparative psychologists were interested more in similarities than differences in behavior; they were seeking general laws of behavior, especially relating to development, which could be applied to all animal species, including humans.
- Ethologists focused primarily on lab experiments involving a handful of species, mainly rats and pigeons, whereas early ethologists concentrated on behavior in natural situations, tending to describe it as instinctive.
The differences have been characterized as study of general processes (psychology) versus a study of adaptive specialization (ethology) (26).
The two approaches are complementary rather than competitive, but they do lead to different perspectives and sometimes to conflicts of opinion about matters of substance. In addition, for most of the twentieth century, ethology, which had developed in Europe, failed to gain a strong foothold in North America, where comparative psychology was dominant. However, in the 1970s, a rapprochement was achieved, and today, animal behavior is a more integrated discipline, with comparative psychologists and ethological animal behaviorists working on similar problems and publishing side by side in the same journals.
Methodology
Tinbergen's four questions for ethologists
(tradition of hypothesis-driven research) Lorenz's collaborator, Niko Tinbergen, argued that ethologists should consider the following four categories when attempting to formulate a hypothesis that explains any instance of behavior:
- Function: how does the behavior impact the animal's chance of survival and reproduction?
- Mechanism: what are the stimuli that elicit the response? How has the response been modified by recent learning?
- Development: how does the behavior change with age? What early experiences are necessary for the behavior to be demonstrated?
- Evolutionary history: how does the behavior compare with similar behavior in related species? How might the behavior have arisen through the process of phylogeny (define)?
Using fieldwork to test hypotheses
(transition) Other early ethologists, such as Oskar Heinroth and Julian Huxley, instead concentrated on behaviours that can be called instinctive, or natural, in that they occur in all members of a species under specified circumstances. Their first step in studying the behavior of a new species was to construct an ethogram (a description of the main types of natural behavior with their frequencies of occurrence). This approach provided an objective, cumulative base of data about behaviour, which subsequent researchers could check and build on.
Neuroethology is a branch of neuroscience that emphasizes the study of neural mechanisms of natural behavior. As an example, consider the study of hearing in an echolocating bat. A species of bat may use frequency chirps to probe the environment while in flight. A traditional neuroscientific study of the auditory system of the bat would involve anesthetizing it, performing a craniotomy to insert recording electrodes in its brain, and then recording neural responses to pure tone stimuli played from loudspeakers. In contrast, an ideal neuroethological study would attempt to replicate the natural conditions of the animal as closely as possible. It would involve recording from the animal’s brain while it is awake, producing its natural calls while performing some natural behavior such as insect capture.
Key principles and concepts
Behaviors are adaptive responses to natural selection
Because ethology is understood as a branch of biology, ethologists have been particularly concerned with the evolution of behavior and the understanding of behavior in terms of the theory of natural selection. In one sense, the first modern ethologist was Charles Darwin, whose book The Expression of the Emotions in Man and Animals (1872) has influenced many ethologists. Although Darwin’s protégé George Romanes became one of the founders of comparative psychology, positing a similarity of cognitive processes and mechanisms between animals and humans, something on neo-Darwinism.
Animals use fixed action patterns in communication
An important step, associated with the name of Konrad Lorenz though probably due more to his teacher, Oskar Heinroth, was the identification of fixed action patterns (FAPs). Lorenz popularized FAPs as instinctive responses that would occur reliably in the presence of identifiable stimuli (called sign stimuli or releasing stimuli). These FAPs could then be compared across species, and the similarities and differences between behaviour could be easily compared with the similarities and differences in morphology. An important and much quoted study of the Anatidae (ducks and geese) by Heinroth used this technique. The ethologists noted that the stimuli that released FAPs were commonly features of the appearance or behaviour of other members of their own species, and they were able to show how important forms of animal communication could be mediated by a few simple FAPs. The most sophisticated investigation of this kind was the study by Karl von Frisch of the so-called "dance language" underlying bee communication. Lorenz developed an interesting theory of the evolution of animal communication based on his observations of the nature of fixed action patterns and the circumstances in which animals emit them.
Waggle dance is a term used in beekeeping and ethology for a particular figure-eight dance of the honeybee. By performing this dance, successful foragers can share with their hive mates information about the direction and distance to patches of flowers yielding nectar or pollen, or both, and to water sources. Thus the waggle dance is a mechanism whereby successful foragers can recruit other bees in their colony to good locations for collecting various resources. It used to be thought that bees have two distinct recruitment dances—round dances and waggle dances—the former for indicating nearby targets and the latter for indicating distant target, but it is now known that a round dance is simply a waggle dance with a very short waggle run (see below). Austrian ethologist Karl von Frisch was one of the first who translated the meaning of the waggle dance.
In ethology, a fixed action pattern (FAP) is an instinctive behavioral sequence that is indivisible and runs to completion. Fixed action patterns are invariant and are produced by a neural network known as the innate releasing mechanism in response to an external sensory stimulus known as a sign stimulus or releaser (a signal from one individual to another).
A mating dance may be used as an example. Many species of birds engage in a specific series of elaborate movements, usually by a brightly colored male. How well they perform the "dance" is then used by females of the species to judge their fitness as a potential mate. The key stimulus is typically the presence of the female.
Another example of a FAP is the red-bellied stickleback (fish). The male turns a bright red/blue colour during the breeding season. This colour change is the fixed action pattern in response to an increasing day length which is the sign stimulus. During this time they are also naturally aggressive towards other red-bellied sticklebacks, another FAP. However anything that is red will bring about this FAP. The proximate response to this is that due to the stimuli, a nerve sends a signal to attack that red item. The ultimate cause of this behavior stems from the fact that the stickleback needs the area in which it is living for either habitat, food, mating with other sticklebacks, or other purposes. This interaction was studied by Niko Tinbergen.
Another well known case is the classic experiments by Tinbergen and Lorenz on the Graylag Goose. Like similar waterfowl, it will roll a displaced egg near its nest back to the others with its beak. The sight of the displaced egg triggers this mechanism. If the egg is taken away, the animal continues with the behavior, pulling its head back as if an imaginary egg is still being maneuvered by the underside of its beak. However, it will also attempt to move other egg shaped objects, such as a golf ball, door knob, or even an egg too large to have possibly been laid by the goose itself (a supernormal stimulus) (Tinbergen, 1991).
Imprinting is a behavior involved in learning
A second important finding of Lorenz concerned the early learning of young nidifugous birds, a process he called imprinting. Lorenz observed that the young of birds such as geese and chickens spontaneously followed their mothers from almost the first day after they were hatched, and he discovered that this response could be imitated by an arbitrary stimulus if the eggs were incubated artificially and the stimulus was presented during a critical period (a less temporally constrained period is called a sensitive period) that continued for a few days after hatching.
Imprinting' is the term used in psychology and ethology to describe any kind of phase-sensitive learning (learning occurring at a particular age or a particular life stage) that is rapid and apparently independent of the consequences of behavior. It was first used to describe situations in which an animal or person learns the characteristics of some stimulus, which is therefore said to be "imprinted" onto the subject.
The best known form of imprinting is filial imprinting, in which a young animal learns the characteristics of its parent. It is most obvious in nidifugous birds, who imprint on their parents and then follow them around. It was first reported in domestic chickens, by the 19th century amateur biologist Douglas Spalding. It was rediscovered by the early ethologist Oskar Heinroth, and studied extensively and popularised by his disciple Konrad Lorenz working with greylag geese. Lorenz demonstrated how incubator-hatched geese would imprint on the first suitable moving stimulus they saw within what he called a "critical period" of about 36 hours shortly after hatching. Most famously, the goslings would imprint on Lorenz himself (more specifically, on his wading boots), and he is often depicted being followed by a gaggle of geese who had imprinted on him. Filial imprinting is not restricted to animals that are able to follow their parents, however; in child development the term is used to refer to the process by which a baby learns who its mother and father are. The process is recognised as beginning in the womb, when the unborn baby starts to recognise its parents' voices (Kissilevsky et al, 2003).
Recent developments in the field
In 1970, the English ethologist John H. Crook published an important paper in which he distinguished comparative ethology from social ethology, and argued that much of the ethology that had existed so far was really comparative ethology—looking at 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.
Indeed, E. O. Wilson's book Sociobiology: The New Synthesis appeared in 1975, and since that time the study of behaviour has been much more concerned with social aspects. It has also been driven by the stronger, but more sophisticated, Darwinism associated with Wilson and Richard Dawkins. The related development of behavioural ecology has also helped transform ethology. Furthermore, a substantial rapprochement with comparative psychology has occurred, so the modern scientific study of behaviour offers a more or less seamless spectrum of approaches – from animal cognition to more traditional comparative psychology, ethology, sociobiology and behavioural ecology. Sociobiology has more recently developed into evolutionary psychology.
Sociobiology: app of behavioral ecology to social behavior, particularly phenotypic altruism and cooperation (some hoopla though surrounding the term over apps to humans; other critcs, which are kind of straw-man arguments, are panglossism and genetic determinism - 29)
Evolutionary psychology – emergent field in that behaviorism banished Darwinism for better part of century; interest in commonalities of cognitive processes in humans and other animals as we might expect natural selection to have shaped them; extension of behavioral ecology
History of the term
The term "ethology" is derived from the Greek word "ethos" (ήθος), meaning "custom." Other words derived from the Greek word "ethos" include "ethics" and "ethical." The term was first popularized in English by the American myrmecologist William Morton Wheeler in 1902. An earlier, slightly different sense of the term was proposed by John Stuart Mill in his 1843 System of Logic. He recommended the development of a new science, "ethology," whose purpose would be the explanation of individual and national differences in character, on the basis of associationistic psychology. This use of the word for this purpose was never adopted.
List of ethologists
People who have made notable contributions to the field of ethology (many are comparative psychologists):
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ReferencesISBN links support NWE through referral fees
- Barnard, C. 2004. Animal Behaviour: Mechanism, Development, Function and Evolution. Harlow, England: Pearson/Prentice Hall. ISBN 0-130-89936-4
- Tinbergen, N. 1991. The Study of Instinct. Reprint ed. New York: Oxford University Press. ISBN 0-198-57722-2
Further reading
- Klein, Z. 2000. The ethological approach to the study of human behaviour. Neuroendocrinology Letters 21:477-81.
External links
- Most popular Internet platform for animal behaviour
- Konrad Lorenz Institute for Evolution and Cognitive Research (KLI)
- Center for the Integrative Study of Animal behaviour (CISAB)
- Introduction to ethology
- Applied Ethology
- The International Society for Human Ethology - aims at promoting ethological perspectives in the scientific study of humans worldwide
- The Four Areas of Biology
- The Four Areas of Biology AND levels of inquiry
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