Personality is a set of characteristics or traits that reflect in one’s cognitive, affective and behavioral states. Personality is based on many factors like heredity or environment.
It may be based on innate or learned experience, or latent or manifest. But, the focus of my essay will be whether a person’s personality is based on the magnitude of genetic or an environmental influence. Personality can be divided into two categories, innate and acquired characteristics.
Heritability is a statistical measure that expresses the proportion of the observed variability in a trait that is a direct result of genetic variability. Environmental influences can be divided into two classes, shared and non-shared environment.
Both heredity and environment contribute to personality traits. Although a person’s environment plays an important part in his personality development, heredity factors play a larger role in deciding disposition of this environment.
Heritability is defined as the proportion of phenotypic variance attributable to the additive effects of genes. A person’s genetic background has a strong influence on his personality. Some personality traits are strongly capable of being inherited by a person.
This can be seen by the comparison of fraternal twins and identical twins, and twins brought up together with twins brought up apart. The aim of such a study is to see which has a greater influence on personality, the genetic background or the environmental influence.
Twin studies showed that identical twins are much more similar than non-identical twins, which suggests genetic influence. Studies have found that identical twins are more similar than fraternal twins on a range of personality measures, indicating that characteristics are heritable.
If a family environment has an influence on personality characteristics, twins brought up together should have more similarities than those brought up apart. Yet, this is not the case. Thus, through twin studies, it can be seen that a person’s personality is based more on heredity rather than environmental influences.
An example is the hereditary of schizophrenia. Initially, the idea that schizophrenia could run in families for genetic reasons was not taken into consideration. Instead, schizophrenia was thought to be environmental in origin, with theories putting the blame on poor parenting.
However, schizophrenia is a hereditary deficiency which no environmental factors can completely counteract. Thus, the individual will be defective, regardless of the type of environmental conditions under which one is being brought up in.
Hans Eysenck also emphasized the biological nature of personality. He argued that personality traits are heritable. Eysenck founded the biological and trait approach and he believed that genetic makeup plays a significant role in the formation of personality. All five factors of Eysenck’s theory (extraversion, agreeableness, conscientiousness, neuroticism, and openness) are heritable.
People inherit more than the global dispositions summarized by the five major personality factors; specific traits such as self-consciousness, gregariousness and openness to ideas are also specifically heritable, and in this regard can better be considered basic tendencies than characteristic adaptations.
Through the study of parental influences, one can see that parenting has a subtle effect on personality. Results of adoption studies showed that children bear little resemblance to either their adoptive parents or their adoptive siblings. Instead, adopted children appear to become more like their birth parents.
For personality, adoptive “siblings” (genetically uncorrelated children adopted into the same adoptive family) correlate near zero, a value implying that shared environment is unimportant and that environmental influence, which are substantial for personality, are of the non-shared variety.
The heritability estimates, as well as estimates of shared and unique environmental influences on personality agree well with those from twin studies in suggesting that the dominant reason for familial resemblance in personality can be traced to genetic factors, with common environment having only a small effect.
Thus, this shows that neither parental role modeling nor parenting practices that would influence all children in a family, seem to have much influence on personality trait.
However, environmental influences also play an important part in the development of a person’s personality. They define the conditions under which human personality changed; they shape a variety of skills, values, attitudes and identities; they provide the solid forms in which personality traits are expressed; and they supply the trait indicators from which personality traits are inferred and trait levels are asserted.
According to Walter Mischel, much of one’s personality is influenced through interaction with the environment. People’s behavior is driven by the situations that they are in rather than by any innate personality traits.
Bandura also argued that personality is the effect of reciprocal determinism- the interaction of behavior, environment and person variables such as perception. Thus, through Bandura and Mischel theories, environmental influences play a part in shaping a person’s personality.
Environmental influence has a pervasive effect on personality traits as well. According to the Five Factor Theory (FFT), personality is biologically based, but it is well established that perceptual and learning experiences can reshape the developing brain. Personality change is linked with life experiences.
Life experience may influence personality through its effects on the brain. Recent studies have suggested that traumatic stress may contribute to atrophy in the hippocampus. Thus, this shows that life experiences influence a person’s personality.
Environmental influences in terms of parenting influences a child’s personality. According to the FFT, the influence of parents on their children is surely incalculable; they nourish, protect, teach them; instills habits, aversions and values and provide some of the earliest models for social interaction and emotional regulation. Therefore, in the long run, parenting has crucial effects for the growth of characteristic adaptation.
For example, birth order has been resurrected as a possible environmental influence for personality development. The younger sibling tend to be more of an extravert than the oldest sibling, as the younger sibling has to try harder for parental attention because of competition from other siblings. Thus, through birth order, it shows how family environment influences one’s personality.
For traits like social attitudes, interests, and even antisocial behavior, the social environment is an important mediating step between primary gene product and behavior. As rose has stated,
“We inherit dispositions, not destinies. Life outcomes are consequences of lifetimes of behavior choices. The choices are guided by our dispositional tendencies, and the tendencies find expression within environmental opportunities that we actively create.”
In conclusion, both hereditary and environmental factors can influence a person’s personality. Heredity sets the limitation which environmental differences decide the concluding result. However, genetic factors have a larger effect on personality traits. Through twins and adoption studies, and the hereditary of schizophrenia,
It can be seen that hereditary has a bigger effect on personality as compared to family environment. Thus, studies of heritability and limited parental influence all point to the notion that personality traits are more of expressions of human biology rather than products of life experiences.