Fixed action pattern

In the study of animal behavior, a fixed action pattern is an instinctive behavioral sequence that is highly stereotyped and species-characteristic. Fixed action patterns are said to be produced by the innate releasing mechanism, a "hard-wired" neural network, in response to a sign/key stimulus or releaser. Once released, a fixed action pattern runs to completion. This term is often associated with Konrad Lorenz, who is the founder of the concept. Lorenz identified six characteristics of fixed action patterns. These characteristics state that fixed action patterns are stereotyped, complex, species-characteristic, released, triggered, and independent of experience. Fixed action patterns have been observed in many species, but most notably in fish and birds. Classic studies by Konrad Lorenz and Niko Tinbergen involve male stickleback mating behavior and greylag goose egg-retrieval behavior. Fixed action patterns have been shown to be evolutionarily advantageous, as they increase both fitness and speed. However, as a result of their predictability, they may also be used as a means of exploitation. An example of this exploitation would be brood parasitism. There are four exceptions to fixed action pattern rules: reduced response threshold, vacuum activity, displacement behavior, and graded response.

In the study of animal behavior, a fixed action pattern is an instinctive behavioral sequence that is highly stereotyped and species-characteristic. Fixed action patterns are said to be produced by the innate releasing mechanism, a "hard-wired" neural network, in response to a sign/key stimulus or releaser. Once released, a fixed action pattern runs to completion. This term is often associated with Konrad Lorenz, who is the founder of the concept. Lorenz identified six characteristics of fixed action patterns. These characteristics state that fixed action patterns are stereotyped, complex, species-characteristic, released, triggered, and independent of experience. Fixed action patterns have been observed in many species, but most notably in fish and birds. Classic studies by Konrad Lorenz and Niko Tinbergen involve male stickleback mating behavior and greylag goose egg-retrieval behavior. Fixed action patterns have been shown to be evolutionarily advantageous, as they increase both fitness and speed. However, as a result of their predictability, they may also be used as a means of exploitation. An example of this exploitation would be brood parasitism. There are four exceptions to fixed action pattern rules: reduced response threshold, vacuum activity, displacement behavior, and graded response. ==Sign stimulus== The sign stimulus, also known as key stimulus or releaser, is the determining feature of a stimulus that produces a response. Sign stimuli are often found when observing a fixed action pattern (FAP) that is an innate behaviour with very little variance in the manner in which the actions are executed. Several examples of sign stimuli can be seen through the observation of animal behaviour in their natural environment. Experimenters have gone into these natural environments to better assess the stimuli and determine the key features of them that elicit a fixed action pattern. Scientists have also observed direct exploitation of sign stimuli in nature among different species of birds. Fixed action patterns are released due to certain external stimuli. These stimuli are single or a small group of attributes of an object, not the object as a whole. These attributes may include color, shape, odor, and sound. Exaggerated models of these attributes are called supernormal stimuli. A supernormal stimulus leads to an exaggerated response. Supernormal stimuli are more effective at releasing a response than a natural stimulus. An external stimulus that elicits a fixed action pattern is termed a sign stimulus if the stimuli emanates from the environment, whereas a releaser emanates from one's own species. ===Supernormal stimuli=== When conducting further experiments, scientists came across the idea of supernormal stimuli. Nikolaas Tinbergen found that incubating geese when given the choice between performing the egg-rolling FAP with an egg versus a full-sized volleyball, they chose the volleyball. These supernormal stimuli, although not naturally occurring, gave insight into the process of natural selection and how it may be that some stimulus features such as the size of the egg result in an increased ability to trigger a FAP. === Other examples of sign stimuli=== More examples of sign stimuli include: The red mark on an adult's beak recognized by the chicks of various gull species. Light polarization patterns recognized by mayflies when they are deciding where to drop their eggs. The presence of a female sage grouse that causes males to exhibit a strut pattern display in order to attract the female during breeding season. ==Further reading== (1998) Animal Behavior: An Evolutionary Approach (6th edition), Chapter 5. Sinauer Associates, Inc. Sunderland, Massachusetts. (2005) Learning and Behavior, (6th Edition). New Jersey: Prentice Hall. de:Instinktverhalten

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