Врожденные модели поведения животных

Instinctive animal behavior
"Fixed action pattern" is an ethological term describing 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. These characteristics state that fixed action patterns are stereotyped, complex, species characteristic, released, triggered, and independent of experience. 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. These attributes may include color, shape, odor, and sound. A supernormal stimulus leads to an exaggerated response.

One example of fixed action patterns is the courtship and aggression behaviours of the male stickleback, particularly the three spined stickleback, during mating season, described in a series of studies by Niko Tinbergen. During the spring mating season, male sticklebacks' ventrum turns red and they establish a territory to build a nest. The sight of the displaced egg is the sign stimulus and elicits the egg retrieval behavior. The sight of the egg outside of the nest serves as the stimulus in this particular instance because it is only after the recognition of the egg's displacement that the fixed action pattern occurs. The manipulation of the sign stimulus through a series of experiments can allow scientists to understand what specific component of the stimulus is responsible the innate behavioral sequence. If the egg were to be picked up and taken away after it is displaced from the nest, the goose still exhibits the same head moving motion even though there is no egg present.

Most behaviors which are both fixed action patterns and occur in more complex animals, are usually essential to the animal's fitness, or in which speed (i. e. an absence of learning) is a factor. Some species have evolved to exploit the fixed action patterns of other species by mimicry of their sign stimuli. 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 nestling will provide higher levels of stimulus with noisier, more energetic behavior, communicating its urgent need for food.

There are 4 exceptions to fixed action pattern rules. Vacuum activity is demonstrated in courtship behavior of ring doves. Male blond ring doves isolated from their own species will resort to courting a pigeon, then a human's hand, and finally expressing courtship activity alone in their box, if they are left alone for a long period of time. This can be seen in sticklebacks. Displacement behavior occurs when the fighting and mating urges are frustrated. A male stickleback chasing another male stickleback stops where their two territories meet and dives to the bottom of the tank, picking something up. This behavior resembles that of nest digging during mating season, but is not released by the proper sign stimulus.

Fixed action patterns may vary in intensity instead of being triggered.