Fixed action pattern 2525143 224905618 2008-07-10T22:55:41Z Pete.Hurd 247615 /* General */ rm links added by 147.114.226.174, not to the point on FAPs [[Image:Larus_Dominicanus.jpg|right|thumb|[[Kelp Gull]] chicks peck at red spot on mothers beak to stimulate regurgitating reflex.]] In [[ethology]], a '''fixed action pattern''' ('''FAP''') is an [[instinct]]ive [[behavior]]al sequence that is indivisible and runs to completion.{{fact|date=November 2007}} 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 known as a '''sign stimulus''' or '''releaser''' (a [[signalling theory|signal]] from one individual to another). ==Examples== [[Image:V31-d-Graugans.JPG|right|thumb|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 (physiology)|stimulus]] is typically the presence of the female. Another example of fixed action patterns 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]], or has the appearance or being 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 [[Konrad Lorenz|Lorenz]] on the [[Graylag Goose]]. Like similar [[waterfowl]], it 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 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]]).<ref>[[Niko Tinbergen|Tinbergen, N.]] (1951) ''The Study of Instinct''. Oxford University Press, New York.</ref> [[Image:Catyawn.jpg|right|thumb|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 [[vestigiality|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{{Fact|date=May 2007}} (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.<ref>Provine, R. R. (1986) Yawning as a stereo-typed action pattern and releasing stimulus. ''[[Ethology (journal)|Ethology]]'' 72:109-122.</ref> ==Mimicry== [[Image:Reed warbler cuckoo.jpg|left|thumb|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 a 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.<ref>Wickler, W. (1968) ''Mimicry in Plants and Animals.'' World University Library, London.</ref> 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 own offspring are likely to die of [[starvation]]. <!-- Second example: Thynnine wasps and orchids (orchid exploiting wasp) --> ==References== {{commonscat|Fixed action patterns}} ===Cited=== <references /> ===General=== *[[Campbell, N. A.]] (1996) ''Biology'' (4th edition), Chapter 50. Benjamin Cummings, New York ISBN 0-8053-1957-3 *[[John Alcock (behavioral ecologist)|Alcock, J.]] (1998) ''Animal Behavior: An Evolutionary Approach'' (6th edition), Chapter 5. Sinauer Associates, Inc. Sunderland, Massachusetts. ISBN 0-87893-009-4 {{NeuroethologyNavbox}} [[Category:Ethology]] [[Category:Neuroethology Concepts]] [[de:Schlüsselreiz]] [[lb:Schlësselreiz]] [[ja:信号刺激]] [[zh:钥匙刺激]] [[ru:фиксированная форма действия]]