Innate releasing mechanism

An innate releasing mechanism (AAM ) was considered as part of the instinct theory of classical ethology as a mediating instance between a key charm and an innate instinct movement. The term was used in this context as a collective term for all services of the nervous system that result in an organism to a filtering incoming stimuli and ensure that there is always only to a certain stimulus " appropriate " behaviors are executed.

This clear definition, however, was "softened " the basis of experimental studies quickly, when it was found that many a AAM can be modified by experience:

• Through the teaching modified AAM ( EAAM ): It has been observed that innate behaviors with learned behaviors form a insoluble complex behavior; this was referred to as modified by learning AAM;
• Acquired triggering mechanisms (EAM ): Numerous acquired triggering mechanisms were (EAM ) was observed, in which stimulus and response are ultimately coupled similarly rigid like a AAM. As the most elementary form of such an EAM, the conditioned reflex be viewed and purchased by imprinting behavior can be assigned here.

AAM and key stimulus

Behavior observers has always been noticed that many newborn animals are immediately able to resume them wholesome food: it Be chick who seem to know immediately after hatching, which is food and how they have to peck feed; whether they are mammals that are pushing immediately to the teats of the mother without any help. Similar to Pavlov's Linking of conditional stimulus and conditional reflex was Konrad Lorenz in 1936, therefore, formulated the concept of the key stimulus: With this simple term, he described a specific stimulus ( an instinctive movement ) sets a specific action in motion. As a "control " that follow a specific "output" leave it to the specific "input", a subsystem of the central nervous system has been postulated to provide an AAM which every instinct movement was upstream of the "input" analyzed ( to filter ) and at the same time activate the individual. So it is the AAM, which prevents the continuously generated according to instinct theory " energy " for certain instinctive movements from being released into inappropriate situations and vice versa ensures that they will be released only in appropriate situations by the individual in a certain inherited way.

In a sense, the AAM so fills the classical behaviorists much cited black box and can be characterized by three properties:

Proof of innate behavior can be done most easily reared in erfahrungslos test animals; fresh from the egg hatched birds had no possibilities for visual perceptions before hatching, for example. This is one of the reasons that virtually all early ethologists in the field of ornithology worked.

• As an example of AAM -mediated coupling of key stimulus and instinctive movement behavior of many young birds can be interpreted: as soon as a parent bird flies to the box, the young birds lock their beaks on - without each individual learning, so at the first hint of Altvogels after hatching of the young.

Since a key stimulus may occasionally fail over long periods of time, according to instinct theory but steady action-specific energy for its associated instinctive movement is provided, the representative of the instinct theory said the " outpouring " of the final action without key stimulus beforehand and then spoke of an idle action (see also: About jumping motion ).

The neurobiological basis of the AAM

The " innate recognition" of a biologically relevant environmental situation has been demonstrated by behavioral scientists and neurophysiologists often and is well established. Less well secured, however, is exactly how the environmental stimulus ( " key stimulus " ) must be constituted, which can be answered given situation thanks to an AAM. The accurate determination of neural ensembles that represent a neurophysiological equivalent of the AAM is so far only been possible in the first approaches.

A further problem is that the AAM has been postulated as purely theoretical construct, ie without any experimental basis. There was initially rather only the observation that animals react obvious even without prior learning to specific environmental stimuli in certain, predictable way, so that they have specific innate environmental knowledge and a specific innate Verhaltensrepertoir. Such coupling between stimulus and response is mandatory but a neurophysiological filter system requires that: Inasmuch as the AAM was a mere logical consequence of the observed, relatively rigid coupling of stimulus and response. Key stimulus and AAM can therefore also experimentally not be studied separately, because a key stimulus is defined by the fact that it causes a certain reaction thanks to a AAM, and conversely, an AAM is defined by the fact that it is associated with a particular key stimulus.

The concept of AAM can thus be regarded more as an epistemological nature philosophical construct and less than a science. It does, therefore, in the current research hardly an issue.

• Nevertheless, it has already been in the 1970s, for example, when water frog ( Rana esculenta ) demonstrated that certain cells of the retina respond only to specific movements of external objects (see: receptive field ), and that the behavior of biologically relevant external objects "prey" and activate the "enemy" different groups of neurons. However, the findings also talked to ensure that there are no specific nerve cells for a particular object, such as " fly " or " worm," but that the " recognition" of behaviorally relevant stimuli of the environment is the result of collaboration of different neuron classes at different sites in the brain of the frog.

Examples

• People feel sympathy and " protective instinct " for being the " chubby " are stocky and, since they correspond to the baby schema and thus resemble infants. This must be about people not necessarily. Thus, for example, overweight adults and seals because of their shape perceived as cute because of their " greasy " appearance or arctic foxes and chubby cartoon characters. Since a stocky body also occurs in non-human pups, they generally act cute.
• In birds, the orange color of open beak causes a feeding instinct in blocking young birds. Experimentally, one can also bring birds to stuff food in orange vessels.