Innate release mechanism

an innate release mechanism (AAM) applied in the context of the instinct theory of the classical comparative behavior research as mediating instance between a key attraction and an innate instinct movement. The term was used within this framework as collective term for all achievements of the nervous system, which lead in an organism to a filtering of arriving attractions and ensure that to a certain attraction “suitable” behaviors are always only implemented.

This clear definition was aufgeweicht however due to experimental studies rapidly „“, when one stated that some can be modified a AAM by experience:

  • by learning changed AAM (EAAM): It was observed that innate behaviors with learned behaviors form an indissoluble behavior complex; this was called by learning changed AAM;
  • acquired release mechanisms (EAM): It numerous acquired release mechanisms (EAM) observed, with those attraction and reaction in the long run are just as rigidly coupled as with a AAM. As the probably most elementary form such EAM can the conditioned reflex be regarded and also by coinage acquired behavior can be assigned here.

AAM and key attraction

behavior observers had always been noticeable that many newborn animals are immediately able to take up them beneficial the food: There is Küken, which seem to know after slipping immediately, what fodder is and how they have fodder to picken; mammals, those are without strange assistance immediately to the Zitzen of the nut/mother urge. Similarly Pawlows linkage of conditioned attraction and conditioned reflex had formulated Konrad Lorenz 1936 therefore the concept of the key attraction: This descriptive term it named a specific attraction, which sets a specific action (an instinct movement) on. When „Schaltstelle “, which lets “a specific „output “follow the specific „input, became, a subsystem of the central nervous system postulated, evenly a AAM, which is upstream each instinct movement, which analyze “the input” (filter) and the individual activates at the same time. It is thus the AAM, which produced according to instinct theory continuously “energy” for certain instinct movements prevents in mismatching situations to be set free and for it provides in reverse that her only in the suitable situations of the individual in a certain, ererbten way is set free.

In certain sense the AAM fills thus the Black box quoted by Behavioristen much and can by three characteristics be characterized:

  1. recognizing of a key attraction and the behavior following on it are innate and specific;
  2. without AAM no adequate reaction to a key attraction can take place;
  3. a key attraction the following reaction is stereotyped, since its own AAM and a specific reaction are attributed to each key attraction.

The proof of an innate behavior can be led most easily with experienceless drawn up test animals; freshly from the egg birds slipped had no possibilities for visual perceptions before slipping for example. This is one of the reasons for the fact that as well as all early Ethologen in the area of the Ornithologie active were.

  • As example of an AAM obtained coupling of key attraction and instinct movement the behavior of many young birds can be interpreted: As soon as a parents bird approaches the box, the young birds thus already close its bills up and this without each individual learning, during the first approach of the old bird after slipping the boys.

Since a key attraction can be missing occasionally over long time intervals, according to instinct theory however constantly action-specific energy is made available for it assigned the instinct movement, predicted the representatives of the instinct theory the “Hervorbrechen” to the final action also without key attraction and spoke then of a no-load operation action (see. also: Over jump movement).

the neurobiological basis of the AAM

“innate recognizing” of a biologically relevant environmental situation was proven by behavior researchers and neuro physiologists often and is considered as secured. Less well secured is however, how exactly the environmental attraction (“key attraction “) must be constituted, which can be answered owing to a AAM situation-suitably. Also the exact determination of neural ensembles, which represent a neurophysiological correspondence to the AAM, was possible so far only in first beginnings.

Furthermore problematic it is that the AAM was postulated as purely mental Konstrukt , thus without each experimental basis. There was rather first only the observation that animals react obviously also without previous learning to certain environmental attractions in certain, predictable way that they have thus over specific innate environmental knowledge and a specific innate Verhaltensrepertoir. Such a coupling between attraction and reaction presupposes however compellingly a neurophysiological filter system: To that extent the AAM was a bare logical consequence of the observed, relatively coupling of attraction and reaction stared. Key attraction and AAM can be examined therefore in addition, experimentally separately from each other, because a key attraction is defined by it that it causes a certain reaction owing to a AAM, and turned around is defined a AAM by the fact that it is assigned to a certain Schlüsslreiz.

The concept of the AAM can be regarded thus rather as an epistemological, nature-philosophical Konstrukt and less than a scientific. It plays therefore in the current research hardly still another role.

  • Nevertheless one already proved into the 1970er-Jahren for example with the water frog (Rana esculenta) that certain cells of the retina respond only to completely determined movements of outside objects (see: rezeptives field), and that the behavior-biologically relevant outside objects activate „booty “and „enemy “different groups of neurons. However the findings spoke also for the fact that there are no specific nerve cells for a certain object like „fly “or „worm “, but that „recognizing “behavior-relevant attractions of the environment the result of a co-operation of most different neuron classes in different places is in the brain of the frog.


  • Schleidt, Wolfgang M. (1962): The historical development of the terms “innate releasing pattern and “innate release mechanism” in the Ethologie. In: Magazine for animal psychology 19, S. 697-722.

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