Personality is more than just the way we act; it is who we are. The characteristics that make up a person’s personality are as individualistic as his appearance. Many theories attempt to explain why people behave differently. To neuroscientist Roger Collinger the answer is as simple as one- two- three. That is, three different neurotransmitters defined in his Unified Biosocial Theory of Personality. Collinger explains much of the basis of personality by correlating it to the amount of serotonin, dopamine, and norepinephrine in the brain. However, as straightforward as the theory sounds, all scientist and people alike know that the reasons for our personality cannot be explained by a facile speculation. Still, there will always be the intriguing correlation between the chemicals of our brains and our actions.

To begin, I will discuss serotonin, and my sensitivity toward rejection. I consider myself to be a highly sensitive person; I’m guessing I inherited my genes for producing serotonin from my emotional mother. I constantly worry about what other people think of me, and use it to make a decision on what I wear or even how I act sometimes. When reading about serotonin and how it's the harm avoidance chemical, I immediately knew that I had a relatively low level. Opposite to obsessive-compulsive people, who are thought to have high levels of serotonin, I have tried, but it seems impossible for me to stick to any routine or stay tidy for more than a day. Another reason would be I find myself supremely pessimistic and impulsive when under a load of stress. On the biological sense of things, carbohydrates help the pancreas secrete insulin that absorbs competitors of tryptophan that makes serotonin. Since carbohydrates help to make one feel better, I usually crave bread, cookies and cereal when under a load of stress.

Moving along to the next neurotransmitter, I have reason to believe that a high level of dopamine might run in my family. High levels of dopamine correlate highly with the disorder schizophrenia. I am able to trace back in my family tree to one schizophrenic great-grandfather; it is possible that he had an excessive level of dopamine to pass along to the rest of us. According to the diathesis, the genes are present for a certain disorder, but the environment, in his case one of poverty, affects the release of the disorder. Although not extraordinarily wealthy, my family has been in the upper middle class most of my life. Though my immediate family may have inherited the genes, none of us have become schizophrenic.

Back to dopamine’s affect on personality, Steven Johnson, the author of Mind Wide Open, stated that a higher threshold of dopamine naturally results in a minimal need to please oneself (Johnson pg 152). This is true for me, I don’t need to go sky diving, or bungee jumping to be content with my life; just give me a rainy day and a good book and I’ll be satisfied. On the other hand, according to the Personality article, a lower level of dopamine causes a lack of initiative and motivation, (Personality pg. 163) which is a part of my personality as well. Now how can this be? What I believe has been confused is the idea that once you have a higher level of dopamine, you don’t have the desire to search for more promising activities. In other words, a naturally high dopamine level is satisfied, therefore loses the motivation to go in search of more excitement.

By now I may seem like an apprehensive person, with little motivation for risk taking behavior. The reward seeking neurotransmitter, norepinephrine, is usually correlated to the level of dopamine. Which makes sense; a person who needs a rush to gratify his dopamine level, in turn has rewarded himself, therefore meeting the demands of his norepinephrine- whatever. Nevertheless, the Unified Biosocial Theory states that the three neurotransmitters are independent of each other. This is a shame, because I think I may be one of those “hedonistic” people mentioned by Johnson. Not to any extremes, but I strive for recognition and awards in my everyday life. From the time I was elected treasurer of my third grade class, to the scholarships I received for college, I have always enjoyed being rewarded or accepted. The cause for my desire to be constantly rewarded might come environmentally and biologically from my father. Its not that my mother isn’t indulgent, but combined with my father’s willingness to give a sports car as a Christmas present and send me to the highest costing college on my list might have something to do with it. I can also see in his personality, a desire for material rewards. So in this case it could be a combination of both; I may have inherited the need for rewards, and his style of upbringing caused the trait to magnify.

The three neurotransmitters involved in the biosocial theory, materialized the different aspects of my personality that I’ve been aware of, but didn’t fully understand. I think another part of my personality can be explained with adrenaline. Johnson stated that he experienced a spike in adrenaline on the lie-detector every time he told a joke. I tell jokes in nervous situations whether to myself or others. I would tell a joke to a friend or family member to lighten the mood. Another reason could be that I find their laughter a reward for telling a joke. However, when in a crowd of strangers, or a position where I feel uncomfortable I’ll keep any humorous comments to myself. This could be caused by my fear of being stared at instead of laughed at. A heightened adrenaline level suddenly would make me even more uncomfortable then I already was. Supposedly, people laugh according to your status. If you think you are "better" than someone or just don't like the person you won't laugh at their joke regardless. Instead of the icy cold "What the hell did you say that for?" I just stay silent.

Collinger’s theory explained the basic parts of my personality, but could it explain all of it? Perhaps my taste in clothes or food, or where I like to go on vacation, is a part of my personality that can’t only be explained by the three neurotransmitters. Not everything we chose to do can be explained with chemicals; an equal amount of our personality has to do with our environment. Environment does not only include, our upbringing and place we lived. It also includes who we were born as, what religion, or friends we choose for ourselves. As the saying goes, “To each, his own." Everyone's personality is different, so if you want to learn more about your own personality then find it out for yourself. I listed the books and articles I used for this personal assessment. You might be surprised to find out what you learn about yourself!

Reference:

Johnson, Steven. Mide Wide Open: Your Brain and the Neuroscience of Everyday Life Scribner: New York 2004.

Magnavita, Jeffrey J. Theories of Personality: Contemporary Approaches to the Science of Personality. John Wiley & Sons, INC: New York 2002.

“Chromosome 11: Personality” Genome