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EspañolFIXED ACTION PATTERN
(Redirected from Sign stimulus)
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).[1]
Although fixed action patterns are most common in animals with simpler cognitive capabilities, humans also demonstrate fixed action patterns. For example, infants grasp strongly with their hands as a response to tactile stimulus. This is thought to be a vestigial mechanism where when threatened by a predator a young primate would grab on to a parent's fur so the parent could climb to safety without having to hold its child (see also reflex action). Another FAP shared by some animals, including humans, is yawning, which often triggers yawning in other individuals. Yawns last around 6 seconds and are difficult to stop once initiated. Yawning, whether seen, heard or both, then serves as a releaser in nearby animals.[2]
Some species have evolved to exploit the fixed action patterns of other species by mimicry of their sign stimulus. Replicating the releasing mechanism required to trigger an FAP is known as 'code-breaking'. A well known example of this is brood parasitism, where one species will lay its eggs in the nest of another species, which will then parent its young. A young North American cowbird, for example, provides a supernormal stimulus to its parent, which will cause it to forage rapidly in order to satisfy the larger bird's demands.[3] In a natural situation a nestling will provide higher levels of stimulus with noisier, more energetic behavior, communicating its urgent need for food. Parents in this situation should work extra hard to provide food, otherwise their offspring are likely to die of starvation.
Harvard Social Psychologist Ellen Langer demonstrated FAP's in humans with an experiment which showed that when we ask people to do us a favor we will be more successful if we provide a reason. She demonstrated this by asking a small favor of people using a photocopy machine. If she asked 'May i cut in front of you, I only have 5 pages and am in a rush' 94% of people allowed her to cut ahead. If she just said 'I only have 5 pages may I cut ahead' only 60% allowed her. Her third attempt asking 'I only have 5 pages may I cut ahead because...' had a 93% success rate. Showing that no good reason was needed, just the FAP of having been provided an explanation.
1. Tinbergen, N. (1951) ''The Study of Instinct''. Oxford University Press, New York.
2. Provine, R. R. (1986) Yawning as a stereo-typed action pattern and releasing stimulus. ''Ethology'' 72:109-122.
3. Wickler, W. (1968) ''Mimicry in Plants and Animals.'' World University Library, London.
★ Campbell, N. A. (1996) ''Biology'' (4th edition), Chapter 50. Benjamin Cummings, New York ISBN 0-8053-1957-3
★ Alcock, J. (1998) ''Animal Behavior: An Evolutionary Approach'' (6th edition), Chapter 5. Sinauer Associates, Inc. Sunderland, Massachusetts. ISBN 0-87893-009-4
★ Influence, Robert Cialdini (1998), Chapter 1. Collins ISBN-10: 0688128165 ISBN-13: 978-0688128166
★ http://www.amazon.com/gp/reader/0688128165/ref=sib_dp_pop_ex/102-5352850-7930567?ie=UTF8&p=S00G#reader-link
★ http://www.wjh.harvard.edu/~langer/
Kelp Gull chicks peck at red spot on mothers beak to stimulate regurgitating reflex.
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).
| Contents |
| Examples |
| Mimicry |
| In humans |
| References |
| Cited |
| General |
Examples
The egg rolling behavior of a Greylag Goose is a widely cited example of FAPs.
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).[1]
Yawning behavior is seen in many animals
Although fixed action patterns are most common in animals with simpler cognitive capabilities, humans also demonstrate fixed action patterns. For example, infants grasp strongly with their hands as a response to tactile stimulus. This is thought to be a vestigial mechanism where when threatened by a predator a young primate would grab on to a parent's fur so the parent could climb to safety without having to hold its child (see also reflex action). Another FAP shared by some animals, including humans, is yawning, which often triggers yawning in other individuals. Yawns last around 6 seconds and are difficult to stop once initiated. Yawning, whether seen, heard or both, then serves as a releaser in nearby animals.[2]
Mimicry
Brood parasites provide a supernormal stimulus to the parenting species.
Some species have evolved to exploit the fixed action patterns of other species by mimicry of their sign stimulus. Replicating the releasing mechanism required to trigger an FAP is known as 'code-breaking'. A well known example of this is brood parasitism, where one species will lay its eggs in the nest of another species, which will then parent its young. A young North American cowbird, for example, provides a supernormal stimulus to its parent, which will cause it to forage rapidly in order to satisfy the larger bird's demands.[3] In a natural situation a nestling will provide higher levels of stimulus with noisier, more energetic behavior, communicating its urgent need for food. Parents in this situation should work extra hard to provide food, otherwise their offspring are likely to die of starvation.
In humans
Harvard Social Psychologist Ellen Langer demonstrated FAP's in humans with an experiment which showed that when we ask people to do us a favor we will be more successful if we provide a reason. She demonstrated this by asking a small favor of people using a photocopy machine. If she asked 'May i cut in front of you, I only have 5 pages and am in a rush' 94% of people allowed her to cut ahead. If she just said 'I only have 5 pages may I cut ahead' only 60% allowed her. Her third attempt asking 'I only have 5 pages may I cut ahead because...' had a 93% success rate. Showing that no good reason was needed, just the FAP of having been provided an explanation.
References
Cited
1. Tinbergen, N. (1951) ''The Study of Instinct''. Oxford University Press, New York.
2. Provine, R. R. (1986) Yawning as a stereo-typed action pattern and releasing stimulus. ''Ethology'' 72:109-122.
3. Wickler, W. (1968) ''Mimicry in Plants and Animals.'' World University Library, London.
General
★ Campbell, N. A. (1996) ''Biology'' (4th edition), Chapter 50. Benjamin Cummings, New York ISBN 0-8053-1957-3
★ Alcock, J. (1998) ''Animal Behavior: An Evolutionary Approach'' (6th edition), Chapter 5. Sinauer Associates, Inc. Sunderland, Massachusetts. ISBN 0-87893-009-4
★ Influence, Robert Cialdini (1998), Chapter 1. Collins ISBN-10: 0688128165 ISBN-13: 978-0688128166
★ http://www.amazon.com/gp/reader/0688128165/ref=sib_dp_pop_ex/102-5352850-7930567?ie=UTF8&p=S00G#reader-link
★ http://www.wjh.harvard.edu/~langer/
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psst.. try this: add to faves
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