Behavior and Genetics


Behavior is the aggregate of actions and reactions that are displayed by an organism or object within a specific environment. The environment can be physical, social or otherwise. It is noted that behavior does vary from one environment to the other. There are various determinants of behavior in the universe. One of them is socialization. Socialization imparts on the individual belief systems and values that determine the actions that the individual will take in life. Since the process of socialization varies from one society to the other and from one time to the other, behavior also tends to vary to the same extent. Another determinant of behavior is the physical environment. Some behavioral traits that are displayed by some organisms are adaptations to their environments. And since environments do vary from place to place, adaptation techniques and in extension behavioral traits will also vary. But the most important determinant of behavior in humans and other organisms is genetics. This paper will examine the relationship between genetics and behavior.


Scholars have defined behavior as actions or reactions displayed by any object or organism in nature. The action or reaction is taken in relation to the environment within which the object or organism is to be found. For example, when an organism responds to pangs of hunger by preying on other organisms, this can be viewed as a behavior of the organism in question. Behavior has several traits. It can be conscious, meaning that it is deliberate and planned by the executor. It can also be subconscious, where it takes place automatically without deliberations on the part of the actor. Behavior can also be overt. Here, the act which constitutes behavior is open and clear to the rest of the people in the society. A covert behavior means that it is hidden from the scrutiny of others. There are also instances where the act making up the behavior can be conducted either voluntarily or involuntarily. The former is where the actor has control and will over the act while the latter is a situation where the actor has no control over the act.


Behavior and Genetics

Human behavior is a term used to describe acts attributed to human beings that are dependent on several factors in operation within and without the person. These factors include, but are not limited to, the following: culture, emotions, attitudes and authority. The behavior of any social actor can be described severally: It can be normal, abnormal, acceptable, and unacceptable and other descriptive terms.

Studies on humans and other living organisms have shown that there is a relationship between genetics and behavior. There are some behaviors that are determined by the genetic composition of the organism. However, the same studies have shown that not all behaviors are determined by genetics. Some are determined by, among other things, the social and physical environment within which the actor is operating. This paper is going to try and study whether behavior is determined by genetics.

Objectives of the Study

The major objective of this study is to determine whether behavior is determined by genetics. To achieve the major objective, the writer will be guided by several specific objectives as listed below:

1. determinants of behavior: a brief overview

2. genetics and behavior

3. indicators of genetic basis of behavior

4. other determinants of behavior


Behavior and Genetics

Determinants of Behavior: A Brief Overview

The behavior of any organism is a very complex and sophisticated phenomenon. It is determined and affected by several factors. It is erroneous to believe that one can fully examine the nature of behavior from one perspective only (Hewitt, 2009). The factors determining behavior range from the environment that the behavior takes place within and the genetic make up of the organism, be it human or animal.

Behavioral genetics, a field that was pioneered by Sir Francis Galton, attempts to draw a connection between human behavior and genetics (McInerney, 2008). Despite the fact that Galton did not categorically use the term “genetics” in his studies, a look at his works will leave no doubt that what he implied was that human behavior is determined to some degree by genetics. His studies revealed that some behavioral traits are hereditary, been passed down from the parents to the offspring. This hereditary aspect of behavior can only be explained in term of genetics. Genes are the ones that are associated with passing traits from one generation to the next.

Genetic studies have revealed that human beings and other living organisms have varying genetic traits. These differences indicate that no one organism is exactly identical to the other. Some of these traits that vary include behavioral ones. If differences in attributes of the organisms can be explained in terms of differing genetic heritage, then it will not be far fetched to say that behavior is also genetically determined (Eysenck & Reiss, 2007). This is because some behaviors vary from one organism to the other.

However, genetics is not the only determinant of behavior. There are other considerations that have to be factored in when analyzing behavior. These include the environment within which it is conducted (Deesing, Wallace & Grandin, 2008). A person who lives in a society where violence is shunned will tend to suppress his violent streak. This is despite the fact that violence is a part of him. Due to the nature of the society that he lives within, he will not express this trait. Another person with the same violent streak in a society where it is encouraged will express it in


Behavior and Genetics

his behavior without any hindrances. It is clear from this example that genetics did not play a part in the expression of behavior among the two individuals. Rather, societal control played a major role.

From the above discourse, it can be said that it is true that genetics does determine behavior. However, this is to some extent. There are other significant determinants of behavior. Sometimes, an act have absolutely no genetic basis, while at others, genetics collaborates with other factors in determining it.

Genetics and Behavior

It is a fact beyond doubt that genetics does determine and influence behavior. There has been a raging debate that has pitted genetics against environment as the determinant of human and other living organisms’ actions. Each side of this divide acknowledges the fact that no one factor that solely determines the nature of the behavior.

Behavioral geneticists have utilized three methodologies in their efforts to connect behavior and genetics (McInerney, 2008). The first is family studies, where it has been determined that an offspring inherits half of its gene pool from either of the parents (Deesing et al, 2008). That is why there are some traits that run in families, having been passed over from the parents to the offspring. For example, the parent might have a tendency towards violence, and this might be expressed in his offspring. There are families that have been known to have a larger share of mental cases than is normal in the society. This is explained through the possibility of this trait been genetically transmitted from one generation to the other.

The other methodology that they do utilize is the study of the behavior patterns in twins (Hewitt, 2009). Monozygotic twins exhibit almost identical behavior patterns. The twins may be predisposed towards a choleric or sanguine personality. Genetically, these twins share 100


Behavior and Genetics

percent of their genetic material. Hence, it can be assumed that the behavioral patterns of the two are identical because they are contained within the genetic makeup of the two, which are also identical (Eysenck & Reiss, 2007). On the other hand, dizogotic or fraternal twins share only half of their genetic material. Subsequently, they share only a certain percentage of their behavioral traits.

The other methodology that these scholars use is that of adoption studies. They study identical and fraternal twins who, despite the fact they were born of the same parent, they have been reared under differing environments (McInerney, 2008). These studies have shown that identical twins who have been raised under different conditions do exhibit some identical behavioral traits (Deesing et al, 2008). This can only be explained by the fact they do share in genetic pool. However, the same studies have revealed that the same identical twins do exhibit some differing traits. This is an indication that the socialization of the actor creates an impression on his behavior.

However, it has not been easy to establish the relationship between human behavior and genetics. This is because, for starters, it is hard to define the behavior that is been studied (McInerney, 2008). A case in point is intelligence as a behavior. How can one define it? Does it involve solving complex arithmetic problems? Does it involve succeeding in life? Or is it scoring highly on the famous intelligence quotient test? This means that if defining a behavior is problematic on itself, then explaining how genetics is involved in the dynamics of the same becomes even more problematic.

Another problem is that behavior is a complex phenomenon. This been the case, a multitude of genes is involved in determining one trait (Hewitt, 2009). It becomes difficult then to isolate the particular gene that determines a particular behavioral trait. The shifting nature of the environment within which the subjects under study are operating also makes it very hard to determine which genes are at play in any particular trait exhibited by the individual (Eysenck & Reiss, 2007). For the behavioral genetics studies to be accurate and valid, the conditions under which the studies are conducted have to be maintained at a constant. This is not possible considering the fact that it is hard to study human beings, the major source of interest in these studies, under laboratory controlled environment (McInerney, 2008).


Behavior and Genetics

Indicators of Genetic Basis of Behavior

There are some indicators that have been pointed out by those scholars who believe that behavior does have a biological basis. These are the indicators that they do use as evidence to support their premise. Some of those indicators include the fact that it is observable that specific species display specific behavior patterns (Hewitt, 2009). It is also possible to reproduce behavior patterns from one generation to the other. These are just some of the indicators. Following is a comprehensive analysis of these indicators:

Specificity of Behavior

It is observed that a specific species will exhibit a particular form of behavior, distinct from the others (Hewitt, 2009). Operating from the premise that genetics are the ones that set apart one species from the others, it can be deduced that likewise, genetics determines the behaviors of the different species, setting them apart from each other. Different species have different genetic composition. It is this composition that determines the characteristics of the particular species. Some of these characteristics manifest themselves through the behavior of the organism.

A human being will find it very hard to survive without the support of the significant others in the society. Right from birth, the human child relies very much on the support that is provided by the other people in the society. Without them, the infant will not survive. This trait is carried over to adulthood. This is why the human race has one of the most organized social structures among the animal kingdom (Hewitt, 2009). This behavior can be traced to the genetic make-up of the humans. All the humans share the same basic genetic make up. The same way, this social behavior is shared by majority, of not all, of the human race. The explanation for this is that the genetic inheritance that connects these individuals carries with it the social attribute that is observable among this species.

Compare the above scenario with that one of a wild animal like a turtle. The minute that the


Behavior and Genetics

turtle offspring is hatched, it starts to care for itself. Rarely does it the need the support of other members of the species to survive. The other members become important in rare cases, for example when the turtle wants to mate. Unlike their human counterparts, the turtles do not exhibit a social trait. The genetic composition of the turtle and the human being are very different. This means that the turtle does not have the human gene that is responsible for the social attribute. However, all turtles share the same trait of not been social. This trait is coded in their genetic makeup.

Species that are closely related share some behavioral traits between them. For example, the humans are believed to be very close as a species to the monkey family. This is the reason why there are some basic similarities between the behavior of humans and that of other primates. For example, some primates show a very similar tendency towards social cohesion as human beings. This can be explained by the similarity in some of their genetic traits.

Behaviors can be bred

It is possible to reproduce behavior patterns in successive generations of living things either by design or otherwise (Eysenck & Reiss, 2007). This is what those people who have made it their business to produce thoroughbreds have realized. They know that by selective breeding, they can pass the behavioral traits of one generation to the other generation. The only this can be made possible is if genetics are involved in coding the behavior.

The same can be observed in humans. An offspring of the human race can be seen as exhibiting distinctive characteristics that are particular to his family line. These characteristics are passed on through the genes of the parents.

Change in Biological Structures and Processes Leads to Changes in Behavioral Patterns


Behavior and Genetics

If a structure of a living organism is altered, this may lead to change in the processes of the organism that has been affected. This is a case that can be vividly captured by the effects that hormonal treatment has on human subjects. A human male who receives hormonal treatment using the female hormones tends to exhibit traits that are similar to those of females and vise versa (McInerney, 2008).

In recent years, geneticists have discovered that it is possible to alter the traits of a certain organism by inserting within its genetic makeup genes of another organism. For example, a laboratory rat can be treated with a gene from a dog and exhibit traits similar to those of a dog, for example ferocity. This means that ferocity in dogs is attributable to that particular gene that the researchers are able to isolate and inject the rat with it.

Evolutionary History of Behavior

This history does persist across species that are closely related. The relationship between the species has been established to be based on their genetic composition (Deesing et al, 2008). A case in point is the relationship between human beings and other primates, like the chimpanzees. Archeologists argue that humans and the chimpanzees evolved from the same relatives. As such, they share a lot of genetic materials. In fact, it is believed that humans and the chimpanzees share 98% of their genetic makeup (McInerney, 2008).

This is the reason why humans share a lot of behavioral characteristics with the chimpanzees. Both are social, nurture their young and exhibit some facial expression that can be described as similar. All these similarities emanate from the wealth of genetic materials that is shared between the two. The few differences between the behavioral characteristics of the two can be attributed to the 2% differences in their genetic heritage. For example, humans can vocalize their sounds in words while chimpanzees cannot attain the same fete. This is because of the minor differences in their genetic makeup (Eysenck & Reiss, 2007).


Behavior and Genetics

Other Determinants of Behavior

As is clear from the above discussion, genetics is not the only determinant of behavior, especially in human actors. This is because there are some instances where it becomes hard to explain the basis of the behavior that has been displayed and in terms of genetics. Sometimes, there is totally no connection between them.

For instance, Americans tend to be more peaceful and compassionate than Arabs. All of them are human beings, and as such, it can be assumed that they do share the same genetic composition. But how do you explain the differing behavioral traits? The explanation lies in the differences in the environment that they have been brought up in (Hewitt, 2009). The Arabs have been brought up in a culture that exult violence, and so their children and the whole society in extension tends to be violent. Perhaps this is an adaptation to the rough terrain of their surroundings. On the other hand, the Americans are brought up in a society where compassion and empathy is the order of the day. As a result, their children and the whole society in extension tend to display these behavioral traits.

Socialization also plays a very crucial role in determining the nature of the behavior that will be exhibited by the individual (Eysenck & Reiss, 2007). This is what explains the subtle differences between the behavior of identical twins that have been adopted and raised in different cultures. The socialization process will instill norms and beliefs in them, which differ from one society to the other, and which determine their behavior. For example, African identical twins that have been separated will be different to some extent. The one that was raised in America will be technologically savvy than the one brought up in African village context.


The behavior of living organism, be it human or animal, is determined by various factors. The


Behavior and Genetics

interplay of these factors will bring about distinct behavioral traits that set apart one organism from the other. Some of the factors include socialization and the physical environment. However, genetics have been found to play a very major role in determining the behavior of the organism. As such, it can be argued that there is a significant relationship between genetics and behavior. Genetics does play a role in determining behavior. However, this determination should be noted that it is to a certain limit. There are some behaviors that cannot be explained solely on the basis of genetics.


Deesing, N. O., Wallace, J. B & Grandin, B. F. (2008). Genetics versus environment: The big

debate on the causes of behavior. New York: McGraw-Hill, 256-278.

Eysenck, J. P. & Reiss, N. C. (2007). “Genetics and human behavior”. Journal of Personality, 4( 3), 28-29.

Hewitt, N. D. (2009). “The interplay between genetics and socialization in determining human behavior.” Current Directions in Psychological Discourse, 45(3), 48-50.

McInerney, E. X. (2008). “Genetics and behavior in mammals.” Genetics Today, 28(8), 29-34.