‘In an era of genetics, are psychological studies of environmental influences irrelevant?’

The term ‘era of genetics’ emphasises the fact that we have been living in a period of genetics right from the time of the famous scientist Mendel, who first looked at genetic inheritance in the offspring of plants and now we are able to apply his theory and understand why we as humans inherit particular characteristics.

DNA is at the forefront of biological research, and utilising and manipulating information learned from DNA is very important in the twenty first century. An understanding of genetics means we can fight diseases that in the past were fatal and also means that humans can now remove undesirable traits in their offspring.

This question is focused on the nature versus nurture debate, which is the most talked about and significant debate in psychology today. Not only have psychologists tried to tackle this debate, but likewise biologists have, in order to differentiate between the genetic and environmental factors that influence us both physically and psychologically. The extraordinary growth in technology over the past few years has made it much easier to study genetics in greater detail. The Human Genome Project has used the growth in technology to their advantage and has gained extraordinary information through their extensive research. They have learned that the human genome is nearly the same (99.9%) in all people and that almost half of all human proteins (which code for genes) share similarities with other organisms. In this essay I will be looking at the debate in various area of psychology, such as, attachment, language acquisition, aggression and other social aspects.

We would all like for there to be one absolute explanation of what affects our behaviour; either genetics or the environment, but it is impossible because they are not mutually exclusive or independent of one another. This is where the nature versus nurture debate emerges. This argument is based on determining what affects our human development, and whether it is our genetics, ‘nature’, or our environment and the things we are exposed to, ‘nurture’. For example, Kenyans are known as great long distance runners as the country is at high altitude, so their bodies have adapted to this resulting in them having an increased lung capacity but by this example it shows how physiological predispositions can be evolved or worsened by the environment, meaning that their genes could also affect their running ability. The debate still remains, regardless of the subject, whether we are looking at the causes of social or cognitive development and many other aspects in a human’s life.

Many studies in developmental, social and cognitive psychology have been conducted in relation to the debate, and they indicate that there are clear strengths and limitations for each side of the argument. John Bowlby’s (1965) evolutionary theory of attachment greatly supports the nature side of the debate. Bowlby said that the main functions of attachment are affiliation and survival. The mother and the infant both have an innate tendency to form an attachment, it is inborn, something that comes naturally and is not learned which supports the idea that we are genetically programmed to form attachments. Infants form attachments because they need to survive. This is called the evolutionary stable strategy. Bowlby’s study on imprinting showed that babies who were programmed to stay close to their mothers were more likely to survive in harsh hostile conditions. Lorenz said that filial imprinting is not learned by reinforcement or association, rather that it is an inborn biological preparedness to survive. His study with the goslings, that continued to follow him, supports his statement because he was the first thing they saw. Social releasers in an infant elicit care giving; they are inborn characteristics, as children don’t consciously learn to smile or cry, this again supports the idea that infants are genetically programmed to form attachments.

Lamb and Kagan’s temperament hypothesis says that infants are in fact not born as a blank slate, but they carry a general temperament (personality). Some children are outgoing and some can be shy and this can only be explained by genetics, although the suggestion of a blank slate by Locke would mean that a child’s personality is shaped by their exposure to the environment. The formation of attachments can be explained with the nurture theory in relation to classical conditioning (Pavlov, 1879 ), whereby the child learns through association; mainly associating the pleasure of food with the presence of their primary caregiver, and eventually the caregiver becomes the direct source of pleasure irrespective of food, or operant conditioning (Skinner, 1957). In this case the child or carer learns through positive or negative reinforcement and punishment; with the example of food, the caregiver becomes the secondary reinforcer and food is the primary reinforcer. A reinforcer is something that encourages behaviour so that it is more likely to be repeated, for example if a child is hungry and begins to cry, the mother will try to reduce its discomfort by giving the child food; the child’s satisfaction is rewarding and the mother will therefore repeat the action. In this case there are factors beyond genetics in our environment that affect our ability to form attachments. Higher order conditioning can explain the more complicated behaviours that children develop.

Most researchers agree that children acquire language through an interaction of biological and environmental factors. Biologically humans are innately predisposed to learn a language. Chomsky (1975) said that we possess a Language Acquisition Device (LAD), which is an innate mechanism in the brain that facilitates the learning of language. Cross cultural research suggests that language acquisition is universal; it is the same regardless of the language being learned because all languages have the same basic structural foundation. However, the biological theory does not explain how children develop and understanding of grammar, the behaviourist (environmental) theory is used to explain this. Skinner proposed that children learn language in the same way as they learn any other skill, through reinforcement and imitation in operant conditioning and the social learning theory. There are three ways by which children acquire words, they are; Tact, where the child learns via reinforcement as they are rewarded for saying a word correctly; Mand, words are acquired because they serve meaning to the child, and the child learns through association and Echoic, which involves the social learning theory, and the child imitates an adults (model) speech, which is reinforced by a rewarding smile. This explains how children acquire grammar, whereas the biological theory could not do so, emphasising on how relevant and important environmental studies are in psychology.

Studies of genetics provide concrete evidence as they are falsifiable and can be easily tested to establish cause and effect between the variables being looked at whereas some studies of environmental influences are less easily tested and variables can be harder to operationalise, thus making it harder to establish a causal relationship, most especially explanations and studies of aggression in social psychology. Nevertheless, both genetic studies and the environmental studies are needed and neither are irrelevant. There are many explanations as to what causes aggression, the biological approach stating that aggression is caused by our genes, hormones and parts of our neuroanatomy. Research has shown that an increase in testosterone hormone levels is positively correlated with the likelihood of aggression. Likewise, low levels of the neurotransmitter serotonin is linked to high levels of aggression, and also the presence of particular genes can cause aggression. However, even though there is a causal relationship between the various biological causes and aggression, we cannot imply causation and say that these factors have exclusively caused aggression because there may be other reasons such as cognition and socialisation.

An additional problem arises, when we attempt to determine what causes what, the question still remains unanswered as to whether it is genetic information that causes aggression or if aggression causes a change in genetic information and this is why we must take into account studies of environmental influences in order to gain further insight.  Aggression is also said to be learned. Bandura’s Bobo Doll study (1961), illustrated that children learnt to be aggressive by observing models and being vicariously reinforced to imitate the behaviour. The social learning theory shows that biology is not the only cause of aggression, but also what a person is exposed to in their environment can elicit aggressive behaviour, suggesting that a child’s exposure to aggression is as vital as their biological blueprint. Again, no one explanation is adequate enough.

Twin studies are crucial when looking at the nature versus nurture debate. Monozygotic twins are essentially natures own clones and this makes them perfect case studies for psychologists and scientists to be able to determine what affects our human development. The concordance rate in twin studies enables us identify similarities and differences within the twins and to see what causes what in respect to their genetics or the environment. Thomas Bouchard found that in his twenty year longitudinal case study of monozygotic twins separated at birth, there was a common level of genetic influence in certain traits including IQ tests, physical and psychological health, and the concordance rate was similar to twins who had been together all their lives.

A problem arises when we try and determine what causes homosexuality, whether it is genetics or environmental influences, and we can look at twin studies with respect to this. Social norms change over time a great example is homosexuality which was once an abomination in society, but has now become an accepted social norm. The BBC aired in 2009 a documentary called, ‘The Secret Life of Twins’, and in the second episode they followed identical male twins who had lived together all their lives but one was homosexual and the other heterosexual. Genetics alone could not explain this major difference because they were monozygotic twins and had the same distribution of genes and the same DNA, in the documentary the scientists concluded that there is a gene for homosexuality, but it requires something in our environment to trigger the gene to manifest as a phenotype.  This creates emphasises on the fact that nature and nurture are dependent on one another, they both work together to have an impact on human development.

I agree with Anastasi et al’s concept of norm of reaction and I believe that genetics and the environment interact and variation in human behaviour occurs when different environments act on the same genetic pattern resulting in different behaviours or outcomes. Anastasi suggests that a genotype has upper and lower limits. Using the example of the height gene, someone may have the potential to grow up to six feet tall, however if they are in a malnourished environment, they can only grow up to 4 feet. The genetic threshold therefore is large, but ultimately it is the environment that is the deciding factor. The example shows that both the environment and genetics are of importance and neither is irrelevant. In conclusion, I would incur that environmental studies are relevant in an era of genetics; both of them are fundamental factors that influence our human development, but as to which one is of greater importance lies in another debate.

Reference List

Cardwell, M. (1994) A Level Psychology:Early Socialisation, Cognitive Development, Social Behaviour. Longman Group Limited.

Dr Alexander V. Tulleken (2009a) The Secret Life of Twins: London,  Aired by the BBC on 30th September 2009. Documentary: Television.

Dr Alexander V. Tulleken (2009b) The Secret Life of Twins: Article. (Internet) Available from:  http://www.news.bbc.co.uk/1/hi/health/8280431.stm. Accessed 19.06.2010

Johnson, W., Bouchard, et al. (2007). Genetic and environmental influences in the Minnesota Study of Twins Reared Apart. (Internet video) Available from: http://www.youtube.com/watch?v=y_jS-PYSLoQ. Accessed 19.06.2010

Mahoney, N. (2008) Language and Linguistics: Language and Learning. (Internet) Available from: http://www.nsf.gov/news/special_reports/linguistics/learn.  Accessed 19.06.2010

Melton, L., Reza,J. and Jones, I. (2007) Big Picture: Evolution (Issue 5, January 2007)

National Human Genome Research Institute (2010) About the Human Genome Project. (Internet) Available from: http://www.genome.gov Accessed 12.06.2010

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