Is behavior hereditary

Hereditary behaviors

Hereditary behaviors are actions that an individual has carried within himself since birth and that therefore do not have to be learned. Even without the influence of parents or other socialization, these behaviors are mastered.

Unconditional reflex

A reflex is a reaction to a certain dissolving stimulus that occurs over and over again under the same conditions. The reaction is mostly unconscious, involuntary and repeatable as often as desired. Consciousness and will are often not involved in the knee-jerk reaction. Many reflexes serve especially as a protective function. A reflex always follows a clear stimulus-reaction scheme, the so-called reflex arc:

The stimulus is perceived by a receptor and then converted into electrical signals. These are then passed on directly to the central nervous system via the afferent pathways. Reflexes are often about reacting very quickly. Therefore, the pathways here often only lead to the spinal cord instead of to the brain. In the spinal cord, a switch is then made to an efferent pathway that leads away from the central nervous system and towards the target organ and there triggers the end action, i.e. the reaction. If the switch from afferent to efferent pathway only takes place via a synapse, the reflex arc is called monosynaptic. The response time is particularly short here.

There are two different types of reflexes. This is done on the basis of the position of the receptor and effector: In the case of the so-called self-reflex, both the receptor and the successful organ are in the same organ, while in the case of the external reflex, both are in different organs. When it comes to a foreign reflex, there are often several interneurons connected between the afferent and efferent pathways, so that it is not a monosynaptic but a polysynaptic reflex. The latter have a slightly longer response time.


Instinctual act

An instinctual act is also understood to mean offered behaviors that take place over and over again in the same form under the same conditions. The three phases of an instinctual act are called appentence behavior, taxis and final act.

Here, too, a triggering stimulus is needed, but the individual's inner willingness also plays an important role. Here one speaks of the double quantification: Only when both factors are given is an instinctive act triggered in an individual.

The inner readiness is influenced, for example, by the filling level of the stomach, by the concentration of sex hormones or by biological rhythms such as the day-night rhythm. If the final act of the instinctive act has been successfully carried out, the inner readiness usually decreases and the behavior is not carried out again directly.

So-called key stimuli play a special role in instinctive behavior. This is understood to be characteristic stimuli that meet the requirements to trigger instinctive behavior. If the characteristic features of such a key stimulus are simulated, for example with a dummy, these instinctive actions can still be triggered.

Research opportunities

There are various methods of detecting hereditary behavior in animals. A first and relatively inexpensive one is the observation of animals under natural conditions. Young animals have not yet had the opportunity to learn anything, which is why it can be assumed that the behaviors that are carried out shortly after birth are innate. A synchronicity in the execution of the behavior in all individuals indicates a genetic basis.

Another method to check behavior patterns that appear later in life for a genetic predisposition are so-called isolation experiments. If young animals are isolated immediately after birth, they have no opportunity to learn anything from their parents or other individuals in society during development. Therefore, the innate behaviors are particularly evident here.

Some studies on hereditary behavior can also be carried out in humans that are less brutal than isolation shortly after birth. The observation of children born blind and / or deaf, for example, makes it possible to check certain behavior patterns such as facial expressions or gestures for a common genetic component, since these children have many
Behaviors could never learn from others. Behaviors that are homologous in almost all cultures of mankind, such as a smile, also indicate a genetic basis.