Long-term psychological development of identical twins separated at birth - Research Paper Example

Nature versus Nurture: Psychological Development of Identical Twins Separated at Birth The debate of nature versus nurture in identical twins has generated a lot of interest and curiosity in the scientific and psychological worlds. Nature is the one’s inherited qualities that are a function of genes, while nurture is experiences encountered in individual’s life. Many studies have been conducted to assess whether the environment contributes the behavioural characteristics that are not seen in the foetal development of identical twins. Scientists and Psychologists have devoted a considerable time in research to settle this issue through twin adoption studies. They seek to know whether environment influences genetic changes in monozygotic twins. They have endeavoured to establish whether there is environmental influence on personal development and intelligence. To understand whether nature and nurture have a correlation in shaping an individual’s behaviours observed later in life, the essay will explore various twin studies to answer the following questions. 1. Why do we start twin studies, what are the lesson to learn from these studies when the twins are raised in different environments, family structure, socio-economic situations, and education systems. 2. What are the main differences of twins and theory to explain their mental status in teenage and adulthood? Are their psychological issues encountered which contributes to similarities and differences in partner twin. 3. Are there noticeable differences in alcohol alcohol/substance use/abuse and cases studies to explain physical/emotional abuse in either household? 4. What sort of life did the twins live after college and the factors that are attributable to such life? Are there any reasons to belief that their grown up emotional status is related to environment because of the differences in their upbringing? Are there similarities when the twins are raised under differing environments? 5. Is there evidence whether genetics or environment played a major in their psychological health in teenage and adulthood stages? How did the knowledge of separation of the twin play any role in their psychological development negative wise? 6. Does bankruptcy rate, divorce rate, education level, career achievement level have any comparison among twin pairs? Does this data correlate to differences or similarities in environment versus genetics? Adoption twin studies are used to assess whether unshared environmental conditions after birth of identical twins have a role in changes observed in their later life. To find whether it is true that life experiences had effect on genetic make up, Neubauer did a psychological study using Amy and Beth as participants. Neubauer, a psychiatrist in U.S, used Amy and Beth in adoption studies in 1960s (Wright). This happened in New York City. The aim of the research was to determine whether heredity and life experiences contributed to development of twins. The family that adopted Amy was financially unstable while that of Beth was a financially well off one. Amy’s family was unfriendly. In contrast, Beth had a jovial and cheerful family. Amy’s mother was low esteemed and did not speak positively on Amy for the entire period of the ten-year study. She felt that, Amy did not belong to that family and therefore needed little attention. In contrast, Beth’s mother adored her and had a close-knit relationship with her adopted daughter. The mother ensured that Beth got the right attention from all family members. The fathers attended to these girls quite differently. Amy’s father teamed up with her mother to extend the envy towards her. On the other hand, Beth’s father was very supportive. The warmth of this family gave Beth an emotional stability, confidence, and self esteem. Conversely, Amy was low esteemed and less focused because of the poor relationship in the family of adoption (Wright). Identical Twin Studies Identical twins have the same genetic makeup. They are referred to as monozygotic twins since they result from a single fertilized egg. Scientists have used this fact to pursue and ascertain whether heredity (nature) and personal experiences (nurture) have any correlation that influences an individual development. Identical twins are the most preferred tools in this subject because they share same environment during their foetal developmental life. In addition, they are appealing to genetics because of the fact that, they have the same genetic composition. To perform the twin experiments, the scientists and psychologists raises the each twin in a completely different environmental condition. Subjecting the twins to varied developmental surrounding is invaluable to estimate the effects of environment on the genetic makeup of the twins. Since the twins are genetically identical, any change observed in either partner twin is purely associated to unshared environmental conditions. The environmental conditions include, diet, family relations, socio-economic status, and even educational systems and styles. Michel Duyme and Christiane Capron studied the effects of social economic status in the intelligence quotient of identical twins. The participants in this study aged six months and below (Haimwitz). The research findings indicated that, stable social-economic status influenced an increase in intelligence quotient in identical twins reared apart. The findings allude environment has a role in shaping the life of identical twins. Twin Case Studies Identical and fraternal twin studies are different. The fraternal twins do not share hundred percent genetic make up. The identical twins are hundred percent similar in their genetic make up. Thus fraternal twins are not preferred in genetic studies. This is because they have genetic differences and it is difficult to estimate the effects of environment on their genetic make up. Twin case studies have revealed that, there are quite striking differences in the twins raised on different environments. There varied results from these case studies. For instance, the identical twins show differences in physical appearances, such as the mode of dressing, hairstyles, and face makeup (Cardwell and Flanagan 128). However, some case studies show that, there are no changes in variables such as weight and, height. There are conflicting views whether environment affects intelligence quotient. Some researchers argue that, intelligence is attributable to environmental conditions rather than influenced by foetal developmental stages in the mother’s womb. The differences in behaviour of the identical twins is an indication that environment shapes an individual’s development. For instance, good teaching facilities and styles in schools will contribute to greater grades. The partner twin in this environment will demonstrate a lot of command in language expression. He/she will have freedom to associate with other people (Cardwell and Flanagan 127). Good family relationships will have positive impacts to a partner twin under such environment. This is because the emotional needs of the twin partner are well catered. Conversely, sour family relations will affect twins psychologically. This twin will always experience nightmares, disappointments, and sadness. Lack of emotional nourishment has negative impacts on this twin partner (Cardwell and Flanagan 125). Moreover, the twin will lack confidence, compounded by low self-esteem. The observed change is likely to span the twins’ lives. The twins encounter a lot of psychological trauma. For instance, in the case study presented above Amy went a lot of emotional suffering. This affected her growth, and wetted her bed for a period of four years. The twins showed dissimilarities in the way they perceived themselves. Beth was very bold unlike Amy who was cowardice. Another cases study, the Minnesota Study, carried out in 1979 in United States confirmed that, though intelligence was hereditary, environmental factor with sound upbringing contributed to learning abilities in identical twins. This clearly shows that, favourable environments boosts intelligence quotient in identical twins. However, there are variables that are not environmentally influenced. For instance, the findings of Amy and Beth study reported some similarities in their personality. Although Beth’s family was financially well off, she had similar developmental challenges that Amy went through. These included bedwetting, nail-biting, and blanket-clenching in when she was young (Wright). This clearly shows that personality is hereditary. Alcohol and Substance Use/Abuse Twin studies have reported that, substance abuse is genetically and environmentally triggered. Pickens et al conducted a research to ascertain whether drug abuse and substance use was linked to genetic or environment. They used fifty identical twins and sixty four non-identical twins. Their findings indicated that, there was large correlation of drug use/abuse in identical twins than in non-identical twins. They group concluded that substance abuse was not only environmentally influenced but also genetically linked (Wright). Other researchers have devoted their efforts to study whether overindulgence in alcohol, and smoking are genetically triggered or environmentally influenced. In the case study of Amy and Beth, it is evident that, Amy went through emotional distress (Wright). Amy demonstrates this through crying, excessive fear, and nightmares. These psychological and emotional pressure retards her growth. Amy cannot associate well with the other family members and lives a solitary life. When the study ends, Amy has trouble in learning capabilities. The study indicates that, both environment and genetic contribute to drug addition. Raising a partner twin in a family that indulges in alcohol will trigger development of addiction tendencies in that twin partner. Life after the College Some researches show that identical twins behaviour and mannerisms changes after teenage stages. However, other studies indicate that, there are no observable changes in identical twins in their teenage life and adult life. According to Texas adoption project, personality changes as each teen matures to adult stage. This research attributes this change different environmental exposure of the twins. After adolescent stages, identical twins choose different lifestyles. Interests, priorities, preferences, and peers dictate their way of living. Some researches felt that Texas adoption study was misinforming on this matter. In the light of this, Thomas Bouchard conducted a research on separated identical twins to prove whether there was any truth of the personality differences observed in identical twins at maturity. His participants were Oscar Stohr and Jack Yufe. Oscar lived in Europe while Jack was brought up in Caribbean. After they become adult each one chose a different career. Jack entered into politics as a liberal and Oscar as a conservative (Shaffer 84). This indicates that, unshared environment that Jack and Oscar lived shaped their thinking in different ways. Oscar was raised in Nazi-dominated environment. Moreover, he was active in Hitler Youth Movement. This made him to maintain his conservatism nature. In contrast, bringing up Jack in Caribbean culture, made him acquire liberal tendencies (Shaffer 84). A Minnesota twin study is the best study to demonstrate that similarities in identical twins are genetically controlled. In this study, Thomas Bouchard used Jim Lewis and Jim Springer. The two had been separated for 39 years. The study found that, Springer and Lewis liked and hated the same subjects. Their behavioural characteristics were similar. These included smoking, divorce, and drunk the same type of alcohol. Moreover, Springer and Lewis experienced headaches at the same age. Other similarities they shared included, tastes and abilities (Bouchard et al). Evidence for Role of Genetics or Environment Psychological Health in Teenage and Adulthood Stages There is evidence to suggest that environment plays a major role in psychological health of identical twins when they are young. However, follow up studies have not been conducted to ascertain whether the trend observed in childhood and teenage studies replicate in adults. The adoption twin studies of Lily and Gillian in China shows that the separation affected them. They lived with strong memories of each other. This is demonstrated when Gillian’s teacher requested her to draw family members on a paper. Surprisingly, she drew all the family members including her sister Lily whom they were miles apart. The effect of this separation psychologically disturbed Lily most (Demsey). Data on Bankruptcy Rate, Divorce Rate, Education Level, and Career Achievement Level in Twin Studies There are some similarities in divorce rate. The Minnesota twin project revealed that Springer and Lewis divorced same number of times. The Oscar and Jack twin study shows that there are some similarities in career choices. Although, Jack is a liberal and Oscar a conservatism, they have chosen politics. Acquiring sound education in twin is subject to environment. This is because quality education system is perceived to boost intelligence quotient. All these observed differences could be associated to unshared environmental conditions. From the essay it is evident that there are no clear-cut information to whether both environmental conditions and genetic make influence twins developmental stages birth. The case studies of Jim Springer and Jim Lewis support the fact that environment doers not contribute any changes in identical twin reared apart. According to the Minnesota twin research, the twins displayed similarities in every aspect of their life. The unshared environmental conditions of Amy and Beth twin study is a good example that environment affect the developmental stages of identical twins. The similarities observed in such as weight observed in Lewis and Springer can only be associated with their identical genetic makeup. Scientists and psychologist should direct their efforts to settle the debate of nature and nurture. Work cited Bouchard, et al .Sources of human psychological differences: the Minnesota Study of Twins Reared Apart. Web 24 Mar 2012. Cardwell, Mike, and Flanagan, Cara. Psychology A2: The Complete Companion. Cheltenham: Nelson Thornes, 2003. Print. Demsey, Amy. “Identical Twins Adopted from China by two Different Ontario Families Grow up 400 km Apart”. The Star. 3 March 2012. Print. Haimwitz, Avi. Heredity Versus Environment: Twin, Adoption, and Family Studies. Web 23 Mar 2012. Shaffer, David. Social and Personality Development. New Jersey: Cengage Learning, 2008. Print. Wright, Lawrence. Two Lives-- One Personality? Web 23 Mar 2012. Read More