Which do you feel is more important: nature or nurture - Research Paper Example

? Which is more important, nature or nurture? May 28, Introduction Theories on human development had greatly examined the role of nurture or nurture as determinants of human capabilities and behaviors, although recently, some scholars argued that nature and nurture interact in shaping human development (Sameroff, 2010, p.6). Epigenetic mechanisms pertain to molecular events that manage the way the environment controls the genomes of organisms (Powledge, 2011, p.88). They provide evidence that the environment can affect gene expression, which can be shown from twin studies that provide evidence that even twins can have different lifestyles and abilities (Bergin & Bergin, 2012). Behavioral epigenetics is described as “the study of how signals from the environment trigger molecular biological changes that modify what goes on in brain cells” (Powledge, 2011, p.88). Behavioral epigenetics is one the emerging theories of human development that converge nature and nurture theories of human growth. This paper explores these theories and how they affect human development. It demonstrates that despite the role of genes in affecting behavior, nurture remains a powerful variable in shaping human abilities and behaviors. Nature versus Nurture The history of developmental psychology has swung back and forth between the two schools of proponents who stress that individual behavior is “found either in their irreducible fundamental units or in their irreducible fundamental experiences” (Sameroff, 2010, p.7). The nature-versus-nurture paradigm has not only been a dominant content of developmental studies, but also a context for “deterministic thinking” (Sameroff, 2010, p.7). These proponents have shown different evidence and conclusions regarding the determinants of human behaviors and capabilities. This section explores the studies and theorists of the nature-versus-nurture paradigm of human development. Genetics, Mental Capabilities, and Behaviors In several points in history, psychologists and biologists believed in the dominant role of nature in affecting human development. During the 1880s to 1940s, Francis Galton developed the “nature versus nurture” phrase and he expressed that “inherited characteristics were the origins of human nature” (Sameroff, 2010, p.8). The nature proponents waned during the 1920s to 1950s, but gained momentum again during the 1960s to 1970s. Ethology, behavioral genetics, and the cognitive revolution proposed that biology determined human behavior (Sameroff, 2010, p.8). Ethology is the scientific study of animal behavior. Ethologists particularly argued that numerous human behaviors do not need reinforcement in order to be learned (Sameroff, 2010, p.8). They opposed the Stimulus-Response (S-R) theorists and stated that their studies on animals cannot be directly translated and applied to human learning (Sameroff, 2010, p.8). Statistical advances and data from numerous samples of twins enabled behavioral geneticists to emphasize that the effects of genes and environments could be divided, and that genetic differences are enough to explain significant behavioral differences (Defries & McLearn, 1973, as cited in Sameroff, 2010, p.8). Ghodsian-Carpey and Baker (1987) studied the role of genetics and environmental factors in affecting aggression among children. They examined a group of monozygotic (MZ) twins and a group of dizygotic (DZ) twins and compared observed similarities. MZ twins have 100% identical genes, while DZ twins have 50% similarities in their genes on the average (Ghodsian-Carpey & Baker, 1987, p.176). Findings demonstrated that genetic similarity influenced aggressive behaviors and for environmental sources of variance, within-family factors were far more important than the between-family ones. The data also illustrated that significant sex and zygosity differences were identified for certain aggressive behaviors, where males and DZ twins depicted higher aggression than females and MZ twins. Ghodsian-Carpey and Baker (1987) concluded that genetics can directly shape human behaviors, although they considered that gender and environmental factors can also reduce gene expression for aggression. Boutwell, Franklin, Barnes, and Beaver (2011) examined if genetic influences moderate the impacts of corporal punishment on children’s behaviors. They employed statistics from twin siblings that came from a nationally representative data set. Findings showed that genetic risk and corporal punishment can affect behavioral problems for children with genetic risks (Boutwell, Franklin, Barnes, & Beaver, 2011). Jean Piaget provided the foundation of cognitive revolution, where development happens inside the mind of children (Sameroff, 2010, p.8). Cognitive revolution scholars stressed that children needed experiences to make sense of their world, but it did not have any large role in explaining individual differences in human abilities (Sameroff, 2010, p.8). Spinath, Spinath, and Plomin (2008) examined the functions of intelligence and school-related motivation in affecting school achievement. They also studied if sex differences interacted with genetic and environmental variables. Their sampling included 4464 twins, with mean age of nine years old. Spinath, Spinath, and Plomin (2008) investigated how intelligence and school-related motivation affected their intelligence, ability self-perceptions, intrinsic values and achievement scores. Findings showed that girls performed better than boys in English and the former also had higher ability self-perceptions, while boys performed better in Math and scored high in attainment and ability self-perceptions (Spinath, Spinath, & Plomin, 2008). In particular, Spinath, Spinath, and Plomin (2008) observed that genetic influences affected all measures, while having shared environmental variables did not have large effects on intelligence and motivation. Brant et al. (2009) studied the differences in etiology and its impact on the different levels of Intelligence Quotient (IQ). Their sampling including 483 pairs of same-sex twins, who already participated in a longitudinal twin study (LTS). The LTS is a continuing, prospective study of behavioral development that the Institute for Behavioral Genetics (IBG) of the University of Colorado, Boulder conducted (Brant et al., 2009, p.395). The twins were evaluated periodically from ages 1 to 16. Findings showed that a shared environment had a decreasing influence on intelligence, while heritability had an increasing influence across development (Brant et al., 2009). Nonshared environment almost exclusively affected to age to age developments (Brant et al., 2009). Furthermore, the study showed that the developmental etiology of high IQ did not greatly vary from that found for the continuous measure (Brant et al., 2009). Brant et al. (2009) concluded that genetic influences of intelligence are the same for high and average individual abilities. Greven et al. (2009) utilized a genetically informative design to examine the genetic and environmental etiologies of elf-perceived abilities (SPAs), IQ, achievement, and their interconnections in a large sample of twins. Their sampling was composed of “2,287 pairs of twins: 1,217 pairs of monozygotic (MZ) twins and 1,070 pairs of dizygotic (DZ) same-sex twins” (p.753). Findings showed that genetic factors significantly affected SPAs, and that IQ and genetic influences had almost the same effect on SPAs (Greven et al., 2009). Brant et al. (2009) provided evidence that genetic factors primarily explained the connections “phenotypic associations among IQ, SPAs, and achievement” (p.760). They added that genetic overlaps (greater than 50%) also affected IQ, SPAs, and achievement (p.760). These findings from different studies indicated that genetic factors had a larger long-term role in the development of human intelligence and other mental faculties. Even when they acknowledged the role of environmental variables, nature still became a more significant determinant in predicting high and average intelligence, among other mental abilities. Nurture and Impacts on Abilities and Conduct From 1920s to 1950s, the studies of John Watson and Burrhus Frederic “B.F.” Skinner dominated the nurture paradigm. Watson proposed the theory of behaviorism based on Pavlov’s earlier studies (Sameroff, 2010, p.8). Behaviorism operates on the principle of stimulus-response, where external stimuli, which are learned through conditioning, predominantly influence behavior (Sameroff, 2010, p.8). Skinner’s studies indicated that learning is a function of changes in actual behavior (Sameroff, 2010, p.8). Changes in behavior are products of an individual's response to events (stimuli) that take place in the environment (Sameroff, 2010, p.8). Smith (1954) examined the cases of feral children. She noted that nurture provided a primary determinant for behavior and development among these children. She emphasized the role of reinforcement in producing “feral” qualities among children, especially when early childhood conditioning can have quite harmful, long-term effects on children’s mental abilities for speech and human interaction. Nevertheless, Smith (1954) believed that reinforcement throughout childhood and adolescence can decrease or counter the effects of early childhood, where isolation hurt initial chances for normal child development. Several studies showed that environmental factors acted as stimuli for human mental development. Halawah (2006) examined the impact of motivation, family environment, and student characteristics on academic achievement. The study included 388 high school students (193 males and 195 females) from Abu Dhabi District, United Arab Emirates (UAE). Findings showed that motivation directly affected academic achievement, while family environment had the greatest effect on student characteristics. Halawah (2006) concluded that families significantly shaped the cognitive development of children, and that they can continuously affect their subsequent academic success throughout their lifespan. Sekowski and Siekanska (2008) studied the effects of family situation, education, and interpersonal relations on academic success for a group of high achievers. Their sampling included adults (26–35 years old) who in their adolescence (16–19 years old) exhibited exceptional giftedness. They surveyed 90 people who were national academic award winners. They used a control group that was made of 90 people with no outstanding academic achievement. Findings showed significant environmental and personality differences between these groups (Sekowski & Siekanska, 2008). In particular, high achievers belonged to families of higher social and professional status, and nearly 72.2% of them decided to carry on their academic career after they graduated from university (Sekowski & Siekanska, 2008). The national academic award winners also exhibited higher scores in shyness and lower scores in sociability when it came to their interpersonal relations (Sekowski & Siekanska, 2008). Fan (2010) reviewed literature on social factors that affect child development. She mentioned the study of Gabagbui (2002), who discovered that “alcoholism, quarrelsomeness, lack of understanding between spouses and starvation positively correlated with one another to lead to family dysfunction” (cited in Fan, 2010, p.83). These family problems negatively affected children’s emotional behaviors and academic performances (Fan, 2010, p.83). Parenting styles are also known to affect the emotional and academic development of their children. Chen, Dong, and Zhou (1997) examined the association between authoritative and authoritarian parenting styles and social and school adjustment among Chinese children. Their sampling was composed of second-grade children with an average age of eight years old and their parents. Findings showed that both authoritarian and authoritative parenting styles greatly affected children’s academic success and social adjustment in China, which opposed findings in Western societies, where authoritarian parenting led to poor academic scores (Chen, Dong, & Zhou, 1997). Chen, Dong, and Zhou (1997) stressed that authoritarian parenting of both mothers and fathers was “positively associated with aggression-disruption and negatively associated with peer acceptance, sociability competence, distinguished studentship, and school achievement” (p.867). They also underlined that authoritative parenting style was positively related to children’s peer acceptance, social competence, and school achievement and negatively related to children’s social problems. Chen, Dong, and Zhou (1997) concluded that authoritarian and authoritative parenting practices both portrayed the same functions in child rearing that are similar to those found in Western cultures. The study on Brazilian adolescents indicated, on the contrary, that permissive parenting style may be just as good or even better, to some degree, than authoritative parenting (Martinez & Garcia, 2008, p.24). Martinez and Garcia (2008) studied different parenting styles and their impact on child development. Findings showed that Brazilian children of authoritative parents had higher academic and family self-esteem than adolescents that came from neglectful families. In addition, adolescents with indulgent parents had higher family self-esteem and did not greatly vary in academic, social, and physical self-esteem from adolescents who had authoritative parents (Martinez & Garcia, 2008, p.24). Martinez and Garcia (2008) concluded that since Brazilian culture valued acceptance and affection more than individualism and competitiveness, permissive parenting had positive effects on the emotional and intellectual faculties of children. These studies indicated the role of parents in nurturing the social and intellectual growth of their children. Even if these children may have genetic risks for poor behaviors, their parents’ involvement in their lives and studies promoted academic success and positive behavioral developments. The environment also affects the emotional development of children. Votruba-Drzal et al. (2010) studied the effect of early education and care experiences on low-income children and their middle childhood behaviors. They employed data from the Three-City Study, which is a longitudinal study that relied on different data-collection methods. Votruba-Drzal et al. (2010) investigated the status of low-income children and families after the implementation of some social welfare reforms. Findings showed that high-quality early childhood care produced less bad behavior problems during middle childhood (Votruba-Drzal et al., 2010). More responsive, supportive, and systematic care settings resulted to children, who no longer needed to externalize behavior problems by the time they were middle-school students. Findings also showed that these results are principally noteworthy for boys and African American children. Votruba-Drzal et al. (2010) stressed that high-quality early child care facilitated the development of positive childhood behaviors. This study showed that early childhood care impacts the nurturing of children. The cases of feral children already asserted the powerful impact of early childhood influences on the intellectual and social development of children. Hence, nurture theories provide compelling evidence too that social factors affect human development. Nature and Nurture Theories Some scholars argued that nature and nurture both influence human development, and that nurture can even shape the nature of human abilities. Powledge (2011) discussed advances in behavioral epigenetics. Epigenetic modifications to several genes have shown to shape learning and remembering (Powledge, 2011, p.588). J. David Sweatt, director of the McKnight Brain Institute at the University of Alabama at Birmingham, asserted the parallel between developmental processes and the mechanisms of memory, where experience drives memory, in the adult nervous system (Powledge, 2011, p.588). Sweatt said: “It's not just that development and behavioral memory are rough analogs of each other, but rather that they are molecular homologues of each other” (Powledge, 2011, p.588). He stressed that: “…evolution has been efficient in the set of molecular mechanisms that cells use to trigger persisting changes. It uses those mechanisms in development when it's patterning the organism,” and an example is “when it's turning an embryonic stem cell into a neuron or a liver cell” (Powledge, 2011, p.588). He explained: “Then in the adult nervous system it has co-opted some of those same mechanisms to trigger experience-dependent, persisting change in the function of neurons in the nervous system” (Powledge, 2011, p.588). Powledge (2011) stressed that the environment interacts with brain development, which shapes the nature of human behavior. Bergin and Bergin (2012) argued that nature and nurture interact when influencing child development. They gave three principles that direct the interaction between nurture and nature factors (p.235). First, the environment affects gene expression. Second, genes can only affect childhood behaviors when environmental factors reinforce genetic risks. Third, possessing certain genes can make children more vulnerable to environmental influences. Bergin and Bergin (2012) contended that social factors, which directly intermingle with learning among children, can impact their development and even change their genes. Dodge (2004) analyzed secondary sources regarding the nurture and nature debate. He stressed that studies for the previous decade provide persuasive proof that both genes and the environment determine child behaviors. He argued that the most significant discoveries are: the environment can stop or launch gene expression, biology and environment affect one another throughout a person’s lifetime, and the theory of gene-environment fit can be maximized to build up positive behaviors. Dodge (2004) underlined that these findings explained the complex relationships between genetics and socialization, when analyzing and understanding human development. Levine and Munsch (2011) agreed that the environment significantly shapes gene expression. Through genetic evidence, they supported that some genes make people more susceptible to bad or good behaviors. They also used twin studies which showed the effects of genes on alcoholism. However, Levine and Munsch (2011) stressed that cultural and social environments also affect human development. They concluded that genetics, culture and environmental factors altogether influence childhood attitudes and behaviors. Bout well, Franklin, Barnes, and Beaver (2011) stressed in their study too that the confluence of environmental and genetic risk factors was more palpable for boys than girls. They emphasized that spanking children, especially boys, with genetic risks can develop socially unacceptable behaviors, such as aggressiveness and violence. Chen et al. (2011) examined the association between parenting practices and Chinese children’s aggressive behaviors. The sampling was composed of 68 children with a mean age of 4 years old. Findings showed that maternal warmth and guidance reduced aggression levels, while parental power aggression boosted their children’s aggression too (Chen et al., 2011). Non-compliant and defiant children, however, decreased their deviant behaviors more under high parental power aggression. Chen et al. (2011) stressed that parenting style can mitigate the genetic risks of aggressiveness. These studies showed that nature can affect human abilities, but it is up to nature to change that. Conclusion Nature theories asserted that genetics determine people’s abilities and practices. People’s abilities are imprinted in their genes already. Nurture theories, on the contrary, argued that the environment directly affects human development. Socialization, culture, and parenting styles can affect the development of human attitudes and behaviors. Another theory on human nature also emerged. Nature-and-nurture scholars contended that both nature and nurture shape human behavior and that it is even possible for nurture to change gene expression, through the processes of epigenetics. These studies provide a unified approach in understanding human development. In conclusion, nature can affect people’s abilities and practices in life, but nurture can also change their genetic expressions. 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