Genes Affecting Person’s Behavior and Personality

There has been an argument promoted by evolutionary science pundits that our chromosomes are deciding factors in how we behave. However, the question of whether this statement applies to truth remains unanswered. Taking two examples, one may ask if there is strong proof that we as humans act the way we do because of our genetic code, or if the results of our behavior and personality are dictated by our genetics and have little to do with genes. There are several studies that have been conducted in most cases on the data about twins; both identical and fraternal, to test if there is any correlation between their genetics, the way they behave and the types of people they become (in terms of personalities). Whereas some studies have refuted the claim citing lack of provable evidence, others have come to conclusions that genes are important factors which determine a person’s behavior and personality. For instance, in a situation where twins (identical) were separated immediately after birth and raised in diverse environments and show similarities in behavior and personality upon reunion proved that the match or resemblance is genotypic and therefore associated with the genetics of the twins. Behavior geneticists in various research studies have made conclusions that genetics are vital in determining the behavior and personality of a person. As much as there are scientific proofs regarding the connection between genetics, personality and behavior, there are others who have refuted the claims of genetic-behavior/personality relationship arguing that there are identifiable genes specifically responsible for these traits in humans. In other words, there are those who argue that genotypic makeup determines who we are whereas there are those who claim environmental influences affect our behavior and, ultimately, personality. This paper takes a stance that genetics play a plausible role in determining person’s behavior and, to some extent, personality.

Discussion

To begin, a close review is given to works prepared on the basis of data on twins to dissect the stalemate which has occurred in research studies about whether nature or nurture is important regarding a person’s behavior and personality. Identical twins are those whose genotypes are 100% duplicate of each other (Avi n.p). Therefore, it is a suitable case and twins can be used as subjects in studies to indicate whether traits and psychopathology are affected by biology (genetic makeup) or if the environment where the individuals are raised is the major contributor to their behavior and personalities. If one of the identical twins has black hair, for example, it is expected that the second one also has this feature in his/her appearance (Avi n.p.). The same idea of identical genes will also translate into the phenotypes or personality and behavior of these twins. In other words, just like their hair is of the same color, the way they behave and personality types are also expected to have the same traits since they have similarities in genetic makeup.

Non-identical otherwise known as fraternal twins, on the other hand, share only 50% of their genes among themselves as opposed to identical counterparts who share 100% (Avi n.p.). Although fraternal twins are not as successful as identical counterparts in interpreting genes’ influence, their example still can be used as a foundation for comparative studies. In such studies which involve twins, data on both fraternal and identical ones must be used to understand an impact of genes on the issues in question. If biology has stronger effect than the environment, then identical twins are expected to possess more same traits in their psychopathology compared to fraternal ones. Based on this concept, it can be taken as an illustration of heritability coefficient which emerges into action. Therefore, the estimation of the extent to which an individual’s character compares to another person’s under a specific characteristic is linkable to genes, and the coefficient should thus be higher among identical twins as compared to fraternal ones. However, it is also arguable that although identical twins share 100% of their genes, they can go through completely different life experiences. Those can shape the way their behavior, psychopathology, and personality in a manner that brings about some uniqueness in them when compared. The core concept here is that identical twins can exhibit diverse external genes expression (phenotypes) although for similar genetic makeup (genotypes) especially in cases of non-shared environments where they are raised upon separation at birth. For example, Avi’s findings show that: “…differences between attitudes of the participants were at least partially correlated to genetic factors. It also showed that attitudes related to self-reported perspectives or to activities were often correlated” (Avi n.p.) and this is a clear indication of what environment partially contributes to a person’s way of behavior.

Apart from the normal behavior ways and personality types witnessed, genetics is also responsible for certain abnormal behavior conducts such as attention deficit hyperactive disorder (ADHD) among children. In their study, Stergiakouli and others discuss that: “…using molecular genetics, that the same risk alleles contributing to ADHD trait levels in the general population also confer risk of ADHD diagnosis and increased symptom severity” (Stergiakouli et al. 324). It is therefore evident that genetics contributes to both positive and negative behavior traits among individuals. In a separate study, Martin and his co-authors also make the same conclusions as Stergiakouli and others that: “…Epidemiological and twin studies suggest that ADHD frequently co-occurs with and shares genetic susceptibility with autism spectrum disorder (ASD) and ASD-related traits” (Martin et al. n.p). In this scenario, Stergiakouli and others’ study has been supported that indeed genetics not only contributes to desirable behavior traits but also some which are undesirable and epidemiologically based and therefore would need clinical intervention to reverse.

Studies have also been conducted with regard to attitudes of identical twins to determine the heritability of this character among them. Genetic variables such as intelligence of identical twins which can also affect a person’s behavior and personality have also been studied at length and conclusive outcomes documented, For instance, Vernon and coauthors mentioned in their study: “Several significant phenotypic correlations were found between each of the four humor styles and the Big-5, and multivariate behavior genetic analyses revealed that these observed correlations were themselves entirely attributable to genetic and non-shared environmental factors” (Vernon et al. 1116). The findings of another study revealed that the variation witnessed in the attitudes of the subjects was to a lesser extent correlated to genetic factors (but more to the factors other than genes) whereas attitudes which were associated with self-reported activities or perspectives were in most cases correlated (Vukasovic and Denis 769). In an example used, attitudes linked to athletics were highly correlated to findings of self-reported abilities of sports. In a nutshell, athletics’ skills which are genetically determined were found to be linked directly to athletics’ attitudes. However, the correlation had a shortcoming in that it is not always assumable that A causes B in every single circumstance. Other underlying factors which need further and intensive research are associated with the cause although to lower extent.

One factor which must be addressed is the issue of the non-shared environment between the twins and how it contributes to causing variations in their behaviors and personalities. It is a strong factor which research studies have indicated as the one that overshadows genetic predispositions as well as experiences of the shared environment. Avi explained: “…even though identical twins possess the same genetic makeup, they may go through different experiences throughout their lives that shape their personality, behavior, and psychopathology in ways that make them unique relative to each other” (Avi n.p.). Anything within the environment which only affects one of the twins and not the other is called a non-shared environment. Some of the non-shared environment experiences are rather strong and cause varying attitudes and self-reported physical abilities and intelligence (Avi n.p.). Further research thus needs to be conducted on why different environments cause varied attitudes and physical abilities as well as intelligence among twins. There is limited knowledge regarding the micro-factors of the environment which plays a role in shaping twins’ behavior conducts and personalities when exposed to different surroundings. Therefore, although genetics is vital in determining a person’s behavior and personality, there are other factors within the environment which are also influential, but the former remains predominant.

Another angle to view this is through examining the relationship between genes and a person’s temperament (Donnellan et al.). Twin studies which apply the use of parent ratings as the overly used method among children show proof of genetic impacts on temperament (Avi n.p.). These studies in many occasions reveal that identical twins compared to their fraternal counterparts are similar with regards to temperamental behavior changes in varying dimensions which encompass shyness, sociability, emotionality, adaptability, approach, distress, activity, and attention. From most studies, the average approximation of how genetic differences cause variability of temperament range between 20 and 60% within subjects (Saudinno). However, there are few exceptional cases but still, there is no persistent pattern of differential heritability through different dimensions. Since temperament is assumedly biologically controlled trait, it is hence not so shocking are the findings that genes influence parent-rated temperament (Saudinno 214). To compare the study with other variables, adopted and genetically non-related children have been chosen as subjects in other studies (Vernon et al.). It is surprising that although findings show consistent results of genetic influence in parent-rated twins’ temperaments, studies conducted on the data on adopted children prove little or sometimes no genetic influence on their (adopted children’s) temperaments as rated by their adoptive parents.

Genes are also important in influencing siblings’ relationships as a type of conduct. There are modest genetic influences which have been found for both the positive as well as negative scopes of sibling relationships (Ferguson). However, the existing shared environmental impacts are crucial in explaining the nature of siblings’ relationships. Therefore, genetics plays considerable role in siblings’ relationship which can be positive (communication, empathy, and companionship among others) and negative (rivalry, hostility, and criticism).

Genetics is also vital in peer group relationships. Peer groups are considered unique compared to family groups as no one can choose a family to be born and peers have the freedom to select whoever they would want to be in their company (Ferguson). They choose each other on the basis of mutual shared attraction. Studies have exhibited that based on genetically influenced characteristics adolescents look for friends with whom they have similarities in terms of behavior conduct. Furthermore, over the course of continued friendship, peers tend to grow alike. There are, however, only a few studies which have examined the correlation between genetics, environment and peer relationships (Ferguson).

The studies conducted to examine the characteristics of peer group have shown strong evidence that indeed genetics influence parents’ point of view of their adolescent children’s peer groups. However, for the adolescents themselves, studies have found that genetic influences are less important regarding personal perception of their companies whereas non-shared environmental factors appear to be rather crucial in their perception of the groups (Rushton, Trudy, and Yoon 1175). Several friendship dimensions have also been linked to genetics such as caring, love, validation, and support (Rushton, Trudy, and Yoon 1178). On the contrary, negative aspects of friendship, for example, betrayal, criticism, and conflict have been associated with the shared environment. Research studies on group relationships have proved that genetics have implications on academic performance and aspirations, popularity, and delinquency (Rushton, Trudy, and Yoon 1180). It is clear from the instances mentioned above that genetics is important in determining who a person will become regarding behavior and personality.

Genetics also is used as an explanation for various situations such as bulimia nervosa and anorexia nervosa as well as obsessive-compulsive abnormalities (Heinrich et al. 81). Different studies have been designed and conducted to unearth the relationship between family genetics and these comorbid disorders (Heinrich et al. 85). Results from some of the research studies have revealed that probands (mostly parents) had issues with such disorders as obsessive-compulsive disorder, depressive disorders, and eating disorders (bulimia and anorexia nervosa) (Heinrich et al. 86). The research concluded that, people who showed characteristics of eating disorders including their close relatives, had a high chance of suffering from the same abnormalities (Heinrich et al. 86). The results of this research are another proof of what influences genetics have on a person’s behavior. Relatives are people who are closely related by blood and therefore share certain characteristics which are determined by genetics (Heinrich et al. 87). It means that when an individual expresses the behavior as it was in the proband relatives, then the only possible explanation is that genetics play a role in influencing how people behave and the personality they show. They further narrate that: “…Personality seems to be most important in explaining alcohol drinking in early adolescence. However, genetic variations in ANKK1 (rs1800497) and HOMER1 (rs7713917) play an equal role in predicting alcohol drinking two years later and are most important in predicting the increase in alcohol consumption” (Heinrich et al.87). In this case, a connection between personality and behavior (alcoholism) and the contributions genetics gives (in predicting future alcoholism as a behavior), have been revealed. The two are therefore inseparable in determining person’s behavior.

In conclusion, it is evident that genetics is a factor that influences an individual’s personality and behavior. It is molded by genetic makeup, who the person will become. Studies have been conducted to compare twins (both fraternal and identical), adopted children, and families on how they resemble each other in character and in terms of personality type. Conclusions derived from the studies have shown that although environment also has a role in influencing people’s behavior, genetics makes the highest implications on a person’s character and personality. Identical twins raised in different environment (non-shared one) may exhibit certain differences in physical abilities, intelligence, and behavior since the different sets of factors they get exposed to are influential in shaping who they become. However, in cases when they are raised in the same (shared) environment, they achieve similar personality traits and behavior tactics proving therefore that genes are crucial in shaping the behavior of a person.

Annotated Bibliography

Avi, Haimowitz. Heredity Versus Environment: Twin, Adoption, and Family Studies. Rochester Institute of Technology, 2005. Retrieved on 28th September 2017 from http://www.personalityresearch.org/papers/haimowitz.html

Avi Haimowitz wrote an article about how genetics is a factor determining the behavior of a person. The article is printed online, it is one of a number of sources on the issue of genetics and its influence on personality, behavior and psychopathology in general. The article was published online in 2005 and is still relevant due to the structure in which it is arranged and the virtue of being an in-depth publication with a lot of scientific information.

In this publication the author provided deep research on twins, adoption, and family. In this research the main argument is that there is no contradiction in the old question which has been asked over years about what is the cause of behavior, psychopathology, and personality. Avi concludes that there are two factors contributing to structural differences among twins and they are genetic and environmental factors. Additionally, the author claims that as much as genetics plays an important role, there will be no all-inclusive answer to explain the factors explaining human behavior, personality, and psychopathology. In other words, the statement is that whereas genetics plays a role, other factors, for instance, environment, also contribute to this issue. Thus genetics is not considered to be the only determinant of human behavior and personality.

The article is of help to deepen the research considering its stance which was also an area of interest; that genetics is a contributing factor to human behavior and personality. It has added information to the existing literature about the topic thereby making it a relevant source of information as far as this research is concerned.

Donnellan, M. Brent, et al. "Genes, personality, and attachment in adults: A multivariate behavioral genetic analysis." Personality and Social Psychology Bulletin 34.1 (2008): pp. 3-16.

Donnellan and others published their article in 2008. It is a research paper which analyzes the association between personality and attachment of a person and genes, especially in case of adults. It is an analysis paper which is based primarily on genetics as a factor which influences personality and therefore attachment of a person.

In a nutshell, the article used behavioral approaches to estimate how genes as well as the environment contribute towards anxieties associated with attachment and avoidance and the overlap which exists between these attachments and five main personality traits. The authors of the article conclude that there is heritability of individual anxieties variations and avoidances linked to attachment relationships and secondly, the main five otherwise known as the Big Five traits result from genetic impacts.

The article is well organized and research methods have been used properly. It is an article which is not only of great interest for genetics scientists but also sociologists and psychologists since the information presented in it suits all these disciplines. It was proper to use it as a source in the research because of the great insight it gives into the research topic. The paper was a rich source of information required in completing the project as the data presented formed, among other parts, the basis of argument. The researchers utilized the simplest methods to present their work so this one is easy to comprehend, Methods used also contributed to the presentation of the results and analysis conduct as a whole. In my opinion, this research paper was rather suitable source to include in the bibliography making up the research project. Based on the topic of the project, the paper did provide a suitable ground to establish the main argument as the project dictated.

Ferguson, Christopher J. "Genetic contributions to antisocial personality and behavior: A meta-analytic review from an evolutionary perspective." The Journal of Social Psychology 150.2 (2010): pp.160-180.

Ferguson’s article was published in the Journal of Social Psychology in 2010. The article is a research paper conducted to analyze how genetics is a contributing factor to antisocial as well as personality behaviors among individuals. The author came to conclusion in the research that there is evidence from behavioral genetics that the variance experienced in antisocial as well as personality (APB) is a result of genetic influence. Various other disciplines such as criminal justice, psychology, and medicine strain to integrate the information contained in this article with the already existing paradigms which primarily focused on learned or external etiology of the antisocial behavior.

Ferguson in his work displayed a meta-analysis of the behavioral etiological research about the antisocial and personality behavior. In his findings, the author presents that close to 56% of the variance witnessed in APB is best described through implications of genetics while 11% is caused by non-shared influences of genetics. Remaining 31% is due to other unique and non-genetic impacts. The author explained his data with regard to evolutionary psychology theory. The paper apart from being used for research purposes is also beneficial especially to those who would need more basic knowledge about the contribution of genetics to human behavior and personality.

The article is a suitable resource material that was used in completing the assignment because it contains in-depth information about the topic being discussed. The fact that it is a research paper conducted in accordance with the principles set for research creates confidence in the facts it presents. This paper was properly designed and is easy to follow. The methods used for data analysis and presentation were carefully chosen.

Heinrich, Angela, et al. "Prediction of alcohol drinking in adolescents: personality-traits, behavior, brain responses, and genetic variations in the context of reward sensitivity." Biological Psychology 118 (2016): pp. 79-87.

Heinrich and others published their article in the Journal of Biological Psychology in 2016. The article is a research paper that tries to review the possibility of alcohol addiction among adolescents with regards to genetic differences in the context of reward sensitivity. Adolescence is a period in life when a person is likely to tread the path of alcohol abuse. One major factor to this development is how sensitive the individual is to the reward on multiple levels.

In the research, Heinrich and others used data from 736 adolescents as the basis to conduct study (their mediate age was 14.37 years). Reward-related personality traits, candidate genes, brain responses, and behavior were evaluated using the structural equation modeling. Personality proved to be the most important determinant in explaining the drinking habit among early adolescents. Another finding of this study was that genetic variations were found to play an important role in prediction future alcohol consumption among the adolescents. In the study, a hypothesis was made that the beginning of alcohol consumption may be pushed more strongly by personality of a person whereas the transition to elevated use of alcohol is contributed more by genetic influence.

The article was chosen to provide information in the research project since it was relevant with regards to the topic under investigation. It was one of the latest publications on the issue and was therefore a great source to provide updates and more recent findings about the topic. I have found this work well organized and the results were shown conclusively.

Martin, Joanna, et al. "Genetic risk for attention-deficit/hyperactivity disorder contributes to neurodevelopmental traits in the general population." Biological Psychiatry 76.8 (2014). Accessed on 6th October from http://www.sciencedirect.com/science/article/pii/S0006322314001085

Martin and others in their research paper discuss that ADHD is viewed as a serious issue for general population. They state that various studies (data on twins was used as well) prove that ADHD mostly occurs together with and shares the susceptibility of genetics with ASD otherwise referred to as autism spectrum disorder. Martin and his co-researchers were interested in determining if the amalgamation of common molecular genetics variants is responsible for predicting ASD and ADHD-related characters in the general population.

Understanding the impact of genetics and the level of its influence on our behavior and personality is not a psychiatrist or a doctor’s alone work. Parents and teachers alike need to be well informed about various health issues so as to know what to do when their children or learners exhibit suspicious characteristics which are associated with genetics. It is important to be aware of this impact because some of the characters associated with genetics issues, especially children can easily be rectified at young age, for instance, through psychotherapy. The paper thus provides that opportunity for those responsible for taking care of children to learn the characteristics of these behavioral disorders at appropriate time when there still exists the possibility to help these children.

The research paper was very informative and elaborated with facts. This study can prove beneficial to various professionals both in medical and sociology disciplines. Parents and teachers as well can also find this paper useful as it gives insight into how various features as exhibited in children start and develop. The study therefore contributed immensely to providing the information needed in completing the paper.

Rushton, J. Philippe, Trudy Ann Bons, and Yoon-Mi Hur. "The genetics and evolution of the general factor of personality." Journal of Research in Personality 42.5 (2008): pp. 1173-1185.

The article authored by Rushton and his fellow authors was published in the Journal of Research in Personality in 2008. The research paper is about the role of genetics in the evolution of personality factor. The paper was a review of three different research studies conducted and the hypothesis was made that the general factors of personality trigger varying individual differences which include such feature as altruism, the EAS temperament trait as well as the Big Five factors of personality.

The study was conducted using data from 214 university students who were each given 36 personality scales to complete. Both identical (MZ) and fraternal (DZ) twins were given 29 5-point rated scales to finish alongside questionnaires in the second study. The third study was on 575 pairs of both identical and fraternal twins who were rated by their mothers using the 25 temperament scale . Twins are mostly used as subjects in such research studies since they are able to give the desired results and this is because they share most of their genetic makeup (MZ share 100% whereas the DZ share 50% of their genes).

The paper is a suitable source relevant in the field and considering the subject being discussed. It comprises attempts to explore extensively how genetics is related to the evolution of human personality traits and behavior. The authors of the paper chose suitable methods to present and analyze data in a way that is easy to understand and follow. I found this piece of scientific information to be a comprehensive one considering authenticity of results presented and discussed. It is a comparative study which examines how different groups of individuals; both twins show behaviors as determined by genetics and how their behaviors change (evolve) over time.

Saudino, Kimberly J. "Behavioral genetics and child temperament." Journal of Developmental and Behavioral Pediatrics: JDBP 26.3 (2005): pp 214-223.

This research paper tries to answer the question how child’s temperament is determined by genetics. The paper presents findings about the crucial relationship between children’s genetic makeup and certain behaviors such as sibling relationship, peer group relations, and family relationship. Additionally, the paper also explores how temperament as a type of behavior conduct is controlled and determined by genetics. Children who are raised in families with parents (probands) being temperamental are most likely to show the same characteristics. The study also found that sibling intolerance was a behavior determined by genes. Most children who are aggressive to their siblings or peers and sometimes other members of the family including parents behaved in such a way because of their genetic makeup. The behavior tendencies presented by children at a tender age without any environmental factors influencing are directly linked to genetic. Therefore, when a child shows a certain character, in most cases it is due to genetics or heredity.

The paper according to me was well presented and results well analyzed in a manner that makes it easy for readers to comprehend. It is an informative study and therefore contributes to providing literature to the body of knowledge about genetics and behavior (temperament) of children. It has one strength and in this case, its ability to explore extensively some data about children. The paper is useful not only for behaviorists alone, but also for parents and teachers who in most cases are children’s caretakers. The study may provide to them the insight into the various behaviors which children exhibit. Using information from this the paper, teachers and parents will understand why children sometimes behave the way they do as well as what part in this conduct is played by genetics. It may enable them to act act wisely to correct behavior.

Stergiakouli, Evie, et al. "Shared genetic influences between attention-deficit/hyperactivity disorder (ADHD) traits in children and clinical ADHD." Journal of the American Academy of Child & Adolescent Psychiatry 54.4 (2015): pp. 322-327.

The study was conducted by Stergiakouli and other co-researchers in 2015 and published in the Journal of Child and Adolescent Psychiatry. In this work authors tried to examine the main characteristic similarities which exist between the genetically influenced and the clinical ADHD. Study hypothesis was that there could be a possible variation in the architecture of genes as witnessed in the psychiatric disorders and behavioral characteristics. The study thus aimed at testing whether polygenic risk scores related to the difference in ADHD character among children in the whole population could predict the possibility of diagnosing ADHD in an independent clinical sample.

Professionals from several fields can rely on this research paper for reference including; teachers, psychiatrists, and doctors alike. The findings presented in the paper provide facts which are necessary in understanding why certain behaviors are exhibited by children. Authors also managed to express the idea that genetics do not just pass desirable behaviors only, but also undesirable ones such as ADHD. In many occasions people tend to think that certain desirable traits are the only characters which genetics explain their heritability. However, this paper reveals that even those which are clinical or psychiatric in nature could be explained through genetics as the main predisposing factors.

The study was a very important source of literature in this project since it gave an opportunity to explore other behaviors which could be determined by genetics. I have found this source of information based on research finding about how certain clinical psychiatric conditions such as ADHD as a behavior among children, could be caused by genetic influence a comprehensive one.

Vernon, Philip A., et al. "A behavioral genetic investigation of humor styles and their correlations with the Big-5 personality dimensions." Personality and Individual Differences 44.5 (2008): pp.1116-1125.

Vernon and others published a research paper which examined the relationship between behavioral genetics and the Big-5 dimensions of personality. The article was published in 2008 and contains rich information about how genetics play an important role in shaping the Big Five personality dimensions.

In the paper, an example of political interest is used to explain the concepts being laid down. For example, Vernon and co-authors report that political interest is a crucial predictor of an individual’s engagement in politics in future. However, there is little known about where these political interests originate from. The research paper was aimed at giving clarifications about the role played by psychological and biological (genetic) factors in the development of interest in politics. The paper has also contributed to the general body of knowledge by estimating the extent of genetic influe