Schème d’action spécifique

A 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. 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 4 exceptions to fixed action pattern rules. These include reduced response threshold, vacuum activity, displacement behavior, and graded response. There are 6 characteristics of fixed action patterns. Fixed action patterns are said to be stereotyped, complex, species-characteristic, released, triggered, and independent of experience. Stereotyped: Fixed action patterns occur in rigid, predictable, and highly-structured sequences. Complex: Fixed action patterns are not a simple reflex. They are a complex pattern of behavior. Species-characteristic: Fixed action patterns occur in all members of a species of a certain sex and/or a given age when they have attained a specific level of arousal. Released: Fixed action patterns occur in response to a certain sign stimulus or releaser. Triggered: Once released, a fixed action pattern continues to completion, even when there are changes in the surrounding environment.