Genetic Influence on Personality - Essay Example

Genetic influence on personality Genetic Influence on Personality (A review of influence of hereditary on personality developments) Genetic influence on personality 2 Genetic Influence on Personality The term personality originated from the Greek word ‘Persona’, which means the mask worn by players on the stage and often refers to the external impression one makes. It is said that personality is intelligence plus character. The famous psychologist G.W Allport defined personality as follows: “Personality is the dynamic organisation within the individual, of those psychological systems that determine his unique adjustment to environment”. Individuals differ in their intelligence, aptitude, interests and personality traits. Francis Galton, founder of Differential Psychology was the one who started the experiments to study the individual differences. Then came, Alfred Binet, father of the intelligence testing who gave a real impetus and significance to the study of individual differences. Generally speaking, Genetics and Environment are the two broad categories which affect the development of a personality. Genetics means the transference of the characteristics of parents to their off-springs through genes in the chromosomes. Genetics is nothing but the all inborn physical and mental traits that one inherits from his parents and ancestors. Now when we think of personality in terms of genetics we must analyse the following things. Personality difference of same family members, , identical and fraternal twins, effect of genetics on fundamental behaviours, Effect of different living styles of twins in their personality. How the physical structure or appearances affect the personality? Do body and its parts have any influence on personality? Every child comes into this world with certain physical and mental features which will guide him throughout his life. He is born with a body and mind which developed from the Genetic influence on personality 3 fertilized ovum he got from his mother and father. He starts life with a specific type of behaviour and a certain sort of temperament. All this traits, mental and physical constitute his heredity. There is considerable evidence that physical traits such as colour of the eye and skin, blood types, colour blindness and the tendencies to be tall or short, follow the laws of genetics. But there is practically no evidence to prove to what extent mental traits such as intelligence and aptitude are inherited. Arguments of Genetics The study of family histories of 177 famous persons in European countries led Sir Francis Galton to conclude that their greatness was due to genetics. A similar study conducted by famous psychologist Dugdale about the Jukes family, a notorious family of criminals, beggars and prostitutes, led him to believe that their notoriety was due to heredity. Another psychologist, Goddard’s study of 480 descendents of the Kalikak family also led the same conclusion. Later psychologist F.N. Freeman’s study of identical twins, fraternal twins, siblings, and cousins too led him to believe that intelligence was inherited. He concluded the coefficient correlation of intelligence test score were: Identical twins-0.9, Fraternal twins-0.6, Siblings-0.5 and Cousins-0.25. By this he showed that blood relationship was directly proportional to intelligence. But modern psychologists are hesitant to believe all these. They attribute the presence of environmental factors to all of the above developments. Had the members of the members of the family been plucked off to a new environment for further research, the result would have been quite different. So we can conclude both genetic and environmental factors affecting the development of personality. Genetic influence on personality 4 Genetic influence on personality 4 “Some identical twins can in many ways be quiet different even if they haven’t experienced major differences in social influence. Yet genetic influence over psychological life is generally quiet powerful’. (David B. Cohen - Stranger in the Nest: Do Parents Really Shape Their Childs Personality, Intelligence, or Character? Page 12). Genetics alone cannot be termed as the reason for personality development. Identical twins sometimes may be having almost equal intellectual level and behaviour. But their social abilities may be different. One may be introvert while the other may be extrovert. This can be because of the difference in genetics of the father and mother. One may get more characteristics of the father while the other that of the mother. “Patterns of genetic and environmental influences on never marrying may be more sex specific than those on divorcee, and may therefore affect the heritability of pair bonding” (L. Mealey. Part, Joseph Lee Rodgers, Commentary on Chapters 1-5, J.R. Udry. Part II:Commentary on Chapters 6-9, David C. Rowe - Page 265) Consider the case of two identical twins in which one may be a divorcee and the other may be a never married one.Though the sexual needs of both are the same because of the difference in their life the influence of genetics on the never marrying may be more sexually oriented than the divorcee. The divorcee has already enjoyed the sexual life while the other couldn’t. So their personality and behaviour will be different “The genetic influence on a fundamental necessary behaviour such as eating does not completely explain variation in that behaviour or its resultant effect”. (Donald W. Pfaff, Wade H. Berrettini, Tong H. Joh, Stephen C. Maxson -Genetic Influences on Neural and Behavioral Functions -Page 391). Even the twins’ behaviour pattern in eating may be different. The liking of one may be different from the other. The style of eating may also be different. One may be fast Genetic influence on personality 5 in finishing the food while the other may be slow. So there are reasons as well which is governing the personal habits. It need not be stressed that physical structure of an individual influences his personality development. A person with a well built body can take part in various activities which provides satisfaction to his various needs. He is accepted by the group and he develops a wholesome personality. But a person who is crippled or ugly is constrained to keep aloof and brood over himself. Here physical factors are not important, but how he takes it which is important. Physical disability always need not make one secluded or withdrawing. He may try to compensate and may become prominent in other field. Thus physical structure which is connected to genetics have a big role in developing personality. Individual’s behavior and personality are highly influenced by the glands. For example individual with a hyper active thymus may exhibit certain infantile characteristics long after the early stages of puberty, when he suppose to have lost them. An individual with hypo thyroidal conditions develops characteristics known as cretinism. He is sluggish, has a thick swarthy skin and is mentally incompetent. “Genetic effects operate primarily in an additive manner appears to be reasonable, although evidence for some non additive genetic influence is beginning to emerge in the domain of personality. Example.; Extraversion”.( Robert N. Emde, John K. Hewitt-Infancy to Early Childhood: Genetic and Environmental Influences on Developmental Change, page 19). Normally the most of the parent behaviour will be added up in the life of their children. But there are some specific cases where the child’s response to some factors might be completely different Genetic influence on personality 6 from the parents’. There are examples where the introvert parents got extrovert children and vice versa. “According to the expert testimony received at trial, it is now thought that genes influence tastes, preferences, personality styles, manners of speech, and mannerisms.”( Anne Fagot-Largeault, Shahid Rahman, Juan M. Torres - The Influence of Genetics on Contemporary Thinking (Logic, Epistemology, and the Unity of Science) - Page 169). Genes have definite influence on general mannerisms. But at the same time there are other factors from the environment also affecting such mannerisms. A person who is inherited with a particular habit or behaviour can change that if he live in a completely different society for a longer period. He will modify his behavioural patterns as per the needs of the new society he is living. Almost all the early psychologists believed that personality is connected with instincts. Today in America, psychological writers are of the opinion that temperament is the internal weather through which personality develops. “As people’s self awareness increases they better understand the prevailing tendencies of their personality that hold sway over so much of what they do and say each day”(Travis Bradberry - The Personality Code Page 36), Even if most of the personality traits belong to heredity, as time passes, self awareness also improved and thereby an adjustment in the personality, based on the environment will take place in most cases. This is quite natural. Genetic influence on personality 7 “In the past few years, a gradual acceptance among criminologists of biological and genetic influence on at least some manifestations of criminal violence” (William Wright-Born That Way: Genes, Behaviour, Personality - Page 237). It is widely accepted that criminals are indebted to their genetics mostly for their criminal nature. Even though environment also have a vital role in that, majority of their character peculiarities are coming from their genetics itself. “Personalities were sometimes first discovered under hypnosis(Carol S. North, Jo-Ellyn M. Ryall, Richard D. Wetzel, Daniel A. Ricci - Multiple Personalities, Multiple Disorders: Psychiatric Classification and Media Influence - Page 145 ). It is very difficult to understand the personality traits of some exceptional people. One who looked matured may not be the same in their private life. We have seen examples of hard core terrorists who look very simple mostly in looks and personality. Such people can be identified through hypnosis only. Their personality peculiarities will be in their sub conscious mind “The starting point in considering the ways in which anxiety might influence beliefs is to assume that individual differences in anxiety depend to some extent on genetic factors”.( Nico H. Frijda, Antony S. R. Manstead, Sacha Bem - Emotions and Beliefs: How Feelings Influence Thoughts (Studies in Emotion and Social Interaction) Page 56) Even two persons coming from the same family might have different levels of anxiety. One may be over anxious while the other may be less. This is again may be because of the difference in the distribution of genes from the parents to them. “Like traditionalism and religiosity traits equally relevant to ultimate socialisation aggression seems to be affected by genetic factors and also by shared home environment”. Genetic influence on personality 8 (David T. Lykken - The Antisocial Personalities Publisher: Lawrence Erlbaum; 1 edition (May 1, 1995)- Page 104). Belief in religion and traditions can be affected by the environment as well. But the characters like aggression mostly governed by genetics and difficult for a person to change because of its inherited nature. In short personality has greatly influenced by genetics. Environment also plays a vital role in developing that. Personality of two persons coming from same family may be different. Even that of identical twins may be different. Most of the human characters influence by genetics. Personality cannot be measured directly sometimes. Criminals are mostly indebted to genetics for their criminal character. Genetics effect are additive. Personality also influence by the effect of certain glands. Physical structure also influences personality. Genetic influence on personality 9 Sources 1. Anne Fagot-Largeault, Shahid Rahman, Juan M. Torres - The Influence of Genetics on Contemporary Thinking (Logic, Epistemology, and the Unity of Science) Page 169 Publisher: Springer; 1 edition (May 23, 2007) 2. Carol S. North, Jo-Ellyn M. Ryall, Richard D. Wetzel, Daniel A. Ricci - Multiple Personalities, Multiple Disorders: Psychiatric Classification and Media Influence Page 145 Publisher: Oxford University Press, USA; 1 edition (January 15, 1993) 3. David B. Cohen - Stranger in the Nest: Do Parents Really Shape Their Childs Personality, Intelligence, or Character? Page 12 Publisher: Wiley; 1 edition (February 12, 1999) 4. David T. Lykken - The Antisocial Personalities - Page 104 Publisher: Lawrence Erlbaum; 1 edition (May 1, 1995) 5. Donald W. Pfaff, Wade H. Berrettini, Tong H. Joh, Stephen C. Maxson - Genetic Influences on Neural and Behavioral Functions - Page 391 Publisher: CRC-Press; 1 edition (November 30, 1998) 6. L. Mealey. Part, Joseph Lee Rodgers, Commentary on Chapters 1-5, J.R. Udry. Part II:, Commentary on Chapters 6-9, David C. Rowe . Genetic Influences on Human Fertility and Sexuality - Theoretical and Empirical Contributions from the Biological and Behavioural Sciences Page 265 - Publisher: Springer; 1 edition (June 1, 2000) 7. Nico H. Frijda, Antony S. R. Manstead, Sacha Bem - Emotions and Beliefs: How Feelings Influence Thoughts (Studies in Emotion and Social Interaction)- Page 56 Publisher: Cambridge University Press; 1 edition (November 6, 2000) 8. Robert N. Emde, John K. Hewitt - Infancy to Early Childhood: Genetic and Environmental Influences on Developmental Change- Page 19 - Publisher: Oxford University Press, USA; 1 edition (April 19, 2001) 9. Travis Bradberry - The Personality Code Publisher: Page36, Publisher - Putnam Adult (April 19, 2007) 10. William Wright- Born That Way: Genes, Behavior, Personality- Page 237 Publisher: Routledge; 1 edition (September 1999) Read More