Are we pre-programmed to learn, think or react in certain ways? How can we begin to test theories relating to our genes and how we feel or behave?
Many questions come to mind when thinking about whether we are “ourselves” because of something genetically inherited. Just the thought of being “you” based solely on genetic makeup is shocking and has even sparked debate between followers of science and religion. How can we begin answering these questions and what tests would be most credible to create undeniable evidence to convince both sides of the spectrum.
A field of psychology is dedicated to researching the relationship between genes and personality. The discipline is called Behavioral Psychology, which combines elements of Psychology, Genetics and Ethnology to find reoccurring behaviors in different populations. It continues to grow rapidly as advancements in technology and research unravel the mysteries of genetics. One such study, mentioned later in this article, follows different sets of twins who did not grow up together and who had never met to see what similarities and differences they share in their personalities.
However, the studies conducted by Behavioral Psychologists are not limited to humans, and focus also on members of the animal kingdom. Research conducted on both animals and humans focuses on the study of traits shared among populations, and are generally very conclusive. Their aim is also to find common patterns occurring in the relationships between shared traits and the physical environment.
After much study, research has not shown that one gene shapes an individual’s entire personality. However, it has been proven that there are personality traits affected by multiple genes, or polygenic inheritance. Polygenic inheritance refers to traits that are influenced by multiple genes, and also the affect of the environment on development.
Since there is so much that still needs to be studied about genetics in general, it is very difficult to trace a gene to a specific personality trait. Scientists cannot fully understand how genes interact with one other but they do know that interactions exist, and that they can enhance personality traits. However, not all personality traits are inherited.
It is equally as difficult to study personality traits and their relationship to environment. There are many roadblocks in trying to create a proper study for this. An example is the inability to test the effects of one’s environment because it could be considered unethical to place someone from a “good” environment into a “bad” one for the sake of testing and/or without their consent. It is for reasons such as this that many tests are considered impossible to conduct on humans, but can be done on animals.
Many more conclusive tests that may be done to study humans would be considered unethical, which is why scientists have to use already existing populations of people and study them in as much detail as possible. Some current studies have lasted many years. Large populations will naturally have subjects change environments as a result of their own life courses, so it is not unethical to observe what is already happening in their lives.
One group of people that has been used for a study of the relationship between genes and personality traits are twins. “Twin studies have proved particularly interesting for psychologists who study genetic personality traits, since twins may develop into remarkably similar people despite being separated at birth. Two twins who have never met, for example, might both decide to become firefighters, suggesting a clear genetic link between their personalities.” (Wisegeek, 2011).
Since 1979, the University of Minnesota has chronicled the stories of more than 60 sets of twins. The twins studied by Psychology Professor Thomas Bouchard and his colleagues are different from those followed in other studies because they were all separated from one another at birth. In every instance, there are eerily similar traits and habits among each of the twins, who did not grow up together and who have never even met one another. Throughout the chronicled cases, many of the twins were not only in very different financial situations, but also had different religious beliefs. But even with environmental differences, the twins ended up sharing everything from the way they danced, their favorite foods and having the same number of children, to their mannerisms and habits.
One set of twins, Oskar Stohr of Germany and Jack Yufe of Israel, could not have had more different upbringings. Oskar was a member of the Hitler Youth during WWII and Catholic, while Jack was raised Jewish. When compared side by side, the results are very surprising. The twins shared everything from “similar speech and thought patterns, similar gaits, a taste for spicy foods and common peculiarities such as flushing the toilet before they used it.”(Peregrine, 2009). Many studies of separated twins conclude with the same results.
Using pairs of twins, scientists have also studied happiness to try to shed light on the complex relationship between genes and personality. Using the “Five-Factor model” (a widely accepted tool that psychologists use to rate personalities), scientists at the University of Edinburgh and the Queensland Institute for Medical Research discovered that “happiness is partly determined by personality traits and that both personality and happiness are largely hereditary.” (West, 2008).
Using this information, they compiled data on happiness by using 900 pairs of twins for a controlled experiment. Results from this study showed evidence that there are connections between certain personality traits and genes. Although certain genes will not automatically make you a happier person, there are many genes that, when working together, can aid in happiness . If one inherits the right traits they can have an edge over others; a mixture of a “right inherited mix” can provide a shield to stress leading to a happier life when compared to someone without this mix.
In addition to happiness, a study published in the Journal of Abnormal Psychology in 2000 shows a serotonin transmitter gene called the 5-HTT being associated with fear. The study, undertaken with guidance from Associate Professor Norman Schmidt of Ohio State University, involved 72 test subjects who were grouped by their 5-HTT gene. The subjects inhaled carbon dioxide, which made them short of breath. After inhaling the carbon dioxide, a normal reaction would be quick anxiety and fear. Individuals with an 5-HTT variation had a higher level of anxiety and fear lasting much longer. The physical effects, among other things, included a faster heart beat, which also contributed to the longer period of fear. Although a gene cannot directly cause increased fear, a gene can make one more prone to fear and anxiety.
People with both the genetic risk factor and the psychological risk factor for anxiety showed the worst response to the fear-inducing experiment. These people seemed to be at risk for responding with more fear when faced with unpleasant bodily symptoms such as they had in this experiment.” (Melville, 2000).
So, do our genes have an effect on our personalities? The short answer is yes. Unfortunately, the long answer is very involved and is dependent on many other factors, which are as difficult to study as the complex genes themselves.
I would like to believe that all people are capable of shaping their own personalities, and that although there may be some truth to the genetic advantages of some, inheriting negative genes can be overcome by our free will, our environment and our experiences.
