Difference between revisions of "Ethology" - New World Encyclopedia
| Line 1: | Line 1: | ||
{{Claimed}}{{Contracted}} | {{Claimed}}{{Contracted}} | ||
| − | [[Image:V31-d-Graugans.JPG|right|thumb|The egg-rolling behavior of the Greylag Goose is a widely cited example of a fixed-action pattern, one of the key concepts used by ethologists to explain animal behavior.]] | + | [[Image:V31-d-Graugans.JPG|right|thumb|The egg-rolling behavior of the Greylag Goose is a widely cited example of a ''fixed-action pattern'', one of the key concepts used by ethologists to explain animal behavior.]] |
'''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. | '''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. | ||
| Line 6: | Line 6: | ||
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. | 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 | + | Ethology emerged as a discipline in the 1920s; its founding practitioners, themselves influenced by the German ornithologist [[Oskar Heinroth]], were [[Konrad Lorenz]], [[Karl von Frisch]], and [[Niko Tinbergen]], who were jointly awarded the 1973 [[Nobel Prize in Physiology or Medicine]] for their contributions to the study of behavior. (maybe construe them as popularizers and synthesizrs of early work of Douglas Spalding, Heinroth, et al.) |
| − | One of the key ideas of classical ethology | + | One of the key ideas of classical ethology is the concept of [[fixed action pattern]]s (FAPs). FAPs are instinctive responses that will occur reliably in the presence of identifiable stimuli (called ''sign stimuli'' or ''releasing stimuli''). For example, the greylag goose, like similar [[waterfowl]], will roll a displaced [[Egg (biology)|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 to engage in egg-rolling behavior, pulling its head back as if an imaginary egg is still being maneuvered by the underside of its beak. 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 been laid by the goose itself (Tinbergen, 1991). |
| − | 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?) | + | 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 - more flexible?) |
| − | Although ''ethology'' as a disciplinary label has largely faded from use, the desire to understand the animal world has made | + | Although ''ethology'' as a disciplinary label has largely faded from use, the desire to understand the animal world has made ethology's intellectual inheritors – such as [[behavioral ecology]] and [[evolutionary psychology]] – rapidly growing fields. Today, students of animal behavior tend to place greater emphasis on social relationships (rather than the individual as variable); however, these studies retain ethology’s tradition of hypothesis-driven investigation and evolutionary focus. |
==Relation to comparative psychology== | ==Relation to comparative psychology== | ||
| Line 32: | Line 32: | ||
* Mechanism: what are the stimuli that elicit the response? How has the response been modified by recent learning? | * 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? | * 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]] ( | + | * Evolutionary history: how does the behavior compare with similar behavior in related species? How might the behavior have arisen through the process of [[phylogeny]] (the development of the species, genus, or group)? |
===Using fieldwork to test hypotheses=== | ===Using fieldwork to test hypotheses=== | ||
| Line 44: | Line 44: | ||
===Animals use fixed action patterns in communication=== | ===Animals use fixed action patterns in communication=== | ||
| − | + | [[Image:Bee dance.png|thumb|left|200px|The honeybee's figure-eight dance is a fixed-action pattern that communicates information to other members of the group: the angle from the sun indicates the direction of a food source; the duration of the dance signifies its distance.]] | |
| − | + | As mentioned above, a ''fixed action pattern (FAP)'' is an [[instinct]]ive [[behavior]]al sequence that is indivisible and runs to completion. Fixed action patterns are invariant and are produced by a [[biological neural network|neural network]] known as the ''innate releasing mechanism'' in response to an external [[sensory system|sensory]] stimulus called the ''sign stimulus'' or ''releaser'' (a [[signalling theory|signal]] from one individual to another). Once identified by ethologists, these FAPs could then be compared across species, comparing similarities and differences in behavior to similarities and differences in form ([[morphology (biology)|morphology]]). | |
| − | |||
| − | [[ | + | An example of how FAPs work in animal communication is the classic investigation by Austrian ethologist Karl von Frisch of the so-called "dance language" underlying [[bee learning and communication|bee communication]]. 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. The dance is a mechanism for recruiting members of the colony to new sites of available resources. |
| − | |||
| − | + | ===Imprinting is a behavior involved in learning=== | |
| − | + | [[Image:Lorenz.gif|thumb|right|300px|Konrad Z. Lorenz being followed by his imprinted geese]] | |
| − | |||
| − | + | ''Imprinting'' describes any kind of phase-sensitive [[learning]] (i.e., learning occurring at a particular age or 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. Lorenz observed that the young of birds such as [[goose|geese]] and [[chicken]]s 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. 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). | |
| − | |||
| − | + | In [[child development]], the term ''filial imprinting'' is used to refer to the process by which a baby learns to recognize its mother and father. The process begins in the womb, when the unborn baby starts to recognize its parents' voices (Kissilevsky et al., 2003). (really?) | |
| − | |||
| − | |||
| − | |||
==Recent developments in the field== | ==Recent developments in the field== | ||
| − | In [[1970]], the [[England|English]] ethologist John H. Crook published an important paper in which he distinguished '''comparative ethology''' from '''social ethology''' | + | In [[1970]], the [[England|English]] ethologist John H. Crook published an important paper in which he distinguished '''comparative ethology''' from '''social ethology'''. He argued that the ethological studies published to date had focused on the former approach—looking at animals as individuals—whereas in the future ethologists would need to concentrate on the social behaviour of animal groups. |
| − | |||
| − | |||
| − | Sociobiology: | + | Since the appearance of [[E. O. Wilson]]'s seminal book ''[[Sociobiology: The New Synthesis]]'' in1975, the study of behaviour has indeed been much more concerned with behavior's social aspects, such as phenotypic altruism and cooperation. Research has also been driven by a more sophisticated version of evolutionary theory associated with Wilson and [[Richard Dawkins]]. |
| − | Evolutionary psychology | + | 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]], behavioural ecology. Evolutionary psychology, an extension of behavioral ecology, looks at commonalities of cognitive processes in humans and other animals as we might expect natural selection to have shaped them. (is evo psych a new term for sociobio?) |
==History of the term== | ==History of the term== | ||
Revision as of 19:57, 25 June 2007
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, themselves influenced by the German ornithologist Oskar Heinroth, were Konrad Lorenz, Karl von Frisch, and Niko Tinbergen, who were jointly awarded the 1973 Nobel Prize in Physiology or Medicine for their contributions to the study of behavior. (maybe construe them as popularizers and synthesizrs of early work of Douglas Spalding, Heinroth, et al.)
One of the key ideas of classical ethology is the concept of fixed action patterns (FAPs). FAPs are instinctive responses that will occur reliably in the presence of identifiable stimuli (called sign stimuli or releasing stimuli). For example, the greylag goose, like similar waterfowl, 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 to engage in egg-rolling behavior, pulling its head back as if an imaginary egg is still being maneuvered by the underside of its beak. 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 been laid by the goose itself (Tinbergen, 1991).
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 - more flexible?)
Although ethology as a disciplinary label has largely faded from use, the desire to understand the animal world has made ethology's intellectual inheritors – such as behavioral ecology and evolutionary psychology – rapidly growing fields. Today, students of animal behavior tend to place greater emphasis on social relationships (rather than the individual as variable); however, these studies retain ethology’s tradition of hypothesis-driven investigation and evolutionary focus.
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 (the development of the species, genus, or group)?
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
As mentioned above, 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 called the sign stimulus or releaser (a signal from one individual to another). Once identified by ethologists, these FAPs could then be compared across species, comparing similarities and differences in behavior to similarities and differences in form (morphology).
An example of how FAPs work in animal communication is the classic investigation by Austrian ethologist Karl von Frisch of the so-called "dance language" underlying bee communication. 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. The dance is a mechanism for recruiting members of the colony to new sites of available resources.
Imprinting is a behavior involved in learning
Imprinting describes any kind of phase-sensitive learning (i.e., learning occurring at a particular age or 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. 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. 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).
In child development, the term filial imprinting is used to refer to the process by which a baby learns to recognize its mother and father. The process begins in the womb, when the unborn baby starts to recognize its parents' voices (Kissilevsky et al., 2003). (really?)
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. He argued that the ethological studies published to date had focused on the former approach—looking at animals as individuals—whereas in the future ethologists would need to concentrate on the social behaviour of animal groups.
Since the appearance of E. O. Wilson's seminal book Sociobiology: The New Synthesis in1975, the study of behaviour has indeed been much more concerned with behavior's social aspects, such as phenotypic altruism and cooperation. Research has also been driven by a more sophisticated version of evolutionary theory associated with Wilson and Richard Dawkins.
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, behavioural ecology. Evolutionary psychology, an extension of behavioral ecology, looks at commonalities of cognitive processes in humans and other animals as we might expect natural selection to have shaped them. (is evo psych a new term for sociobio?)
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):
|
|
|
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
Credits
New World Encyclopedia writers and editors rewrote and completed the Wikipedia article in accordance with New World Encyclopedia standards. This article abides by terms of the Creative Commons CC-by-sa 3.0 License (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article click here for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here:
The history of this article since it was imported to New World Encyclopedia:
Note: Some restrictions may apply to use of individual images which are separately licensed.
