The nature vs. nurture debate is the scientific, cultural, and philosophical debate about whether human culture, behavior, and personality are caused primarily by nature or nurture. Nature is often defined in this debate as genetic or hormone-based behaviors, while nurture is most commonly defined as environment and experience.
The nature vs. nurture debate is an ongoing one. The modern debate often centers around the effect genes have on human personalities as opposed to the influences that early environment and development might have. As cultural mores have changed, so have popular understandings of this debate. In the 1960s, for example, psychologists—and pop culture in general—were heavily influenced by the theories of behaviorism. This theory led to the widespread belief that human personality is primarily influenced by experience and training. It was during this time that researcher John Money attempted to demonstrate that gender was a product of early conditioning by raising a boy, whose circumcision was botched, as a girl. His experiment seemed successful in the beginning but ultimately was a failure.
While nature, or genetics, has been proven to be an important factor in the development of some mental health conditions, such as schizophrenia, bipolar, and major depression, the development of mental illness is not entirely genetic. Nature, or genetics, has been proven to be an important factor in the development of some mental health conditions, such as schizophrenia, bipolar, and major depression: Bipolar, for example, is four to six times more likely to develop when there is a family history of the condition. However, although the importance of genetic factors cannot be denied, the development of mental illness is not entirely genetic. Take identical twins, for example: They share genes, yet if one twin develops schizophrenia, the other twin only has a 50% chance of also developing the condition. This shows that nature, while it plays an important part, is not the only contributing factor.
Another area where researchers may place more emphasis on nature than on nurture is that of addictions. Studies show that alcohol addiction, for example, can recur in families and that certain genes may have an influence over the way alcohol tastes and the way it affects the body.
Certain genetic factors may create a predisposition for a particular illness, but the probability that a person develops that illness depends in part on environment (nurture). When a genetic variant indicates the possibility of development of a mental illness, this information can be used to direct positive (nurturing) behavior in such a way that the condition may not develop or may develop with less severity.
James Fallon, a neuroscientist who discovered that he had the brain of a psychopath, has stated that he believes growing up in a nurturing and loving environment helped him to become a successful adult and may have been effective at preventing him from fully developing traits of psychopathy. Similarly, the basis for addiction is not thought to be entirely genetic by most researchers. Environmental aspects, such as the habits of parents, friends, or a partner, might also be significant factors contributing to the development of an addiction. A genetic predisposition to alcohol addiction may be far more significant if one is routinely exposed to binge drinking or other forms of alcohol abuse and comes to view this as normal alcohol use.
Researchers at the University of Liverpool recently found that while a family history of mental health conditions was the second strongest predictor of mental illness, the strongest predictor was in fact life events and experiences, such as childhood bullying, abuse, or other trauma, supporting the idea of nurture’s significant role in the development of mental health issues.
Several studies done on twins separated shortly after birth reveal that genetics do play a significant role in the development of certain personality characteristics, sexual orientation, and religiosity. The bond between identical twins was also suggested to be genetic by these studies, as 80% of identical twins reported that they felt closer to their twin than they did to their closest friends, despite having just met their twin. One study also suggested that genetics play a significant role in the development of personality: Environment had little effect on personality when twins were raised together, though it did have an effect when they were raised apart.
Many scientists eschew the debate by emphasizing “nature x nurture.” In this schema, nature and nurture are inseparable. Some genes, for example, cannot be activated without certain environmental inputs. The development of vision is a prime example of this. People cannot develop normal sight without exposure to visual stimuli. Similarly, some environmental inputs may be undermined by some genes. For example, some lifelong smokers may never experience smoking-related illnesses, and this may be due at least in part to their genes. Environmental toxins may alter the expression of some genes, and genes for many behaviors presumed to have a genetic basis have not been discovered. Developmental systems theory, among other theories, presents an alternative to this debate that does not require scientists to advocate either for nature or nurture.
Last updated: 05-12-2015