While searching the web I found many good articles which explained how neurotransmitters affect personality. In some cases norepinepherin can encourage quick emotional responses like anger and also discourage logical thinking, while serotonin can cause irritability and a lack of rational emotion. All of them can cause anger, anxiety, depression, insecure feelings, and fear. To find out what the characteristics of personality are, I found another site appropriate. It lists 16 types of personality that are controlled by various combinations of 4 dimensions: extrovert vs. introvert, sensor vs. intuitive, thinker vs. feeler, and judger vs. perceiver. You can see how some of these could be determined by neurotransmitters.
With happiness in particular, a group of psychologists describe it through the set-point idea. The set-point idea contends that there is a genetically determined mood level that can be nudged by life slightly upward or downward, but in the long run will stay about the same for each individual. Therefore, if you win the lottery or become a paraplegic, you will remain close to the same happiness level that you were always at. The 2 doctors say that about half of your sense of well being is determined by your set-point while the other by the sorrows and pleasures of life. By studying the activity in each prefrontal area, happiness and enthusiasm can be detected from worry and agitation. They tested 10 month old babies and then tracked them for several years and still found the measurements of their brain-wave patterns accurate. It was also discovered that an allele for part of the D4 receptor were related to the amount of dopamine that binds.
Thrill seekers or those that are more reserved and reflective seem to arise from a gene on chromosome 11. Yet it is said that behavior ultimately depends on upbringing and opportunity. The thrill seekers have a stronger reaction to dopamine. Though our happiness seems to be determined by our genes, what factor determines what we find stimulating? The paper also says that certain things give a high. The high differs with each person, some get their high from dancing, going new places, murder, writing neurobiology papers, or simply being alive. It does not seem that any of the web pages mention what gene determines the cue for the release of a neurotransmitter. Why does one person get a high from driving sport cars while another achieves the same effect from eating a good meal?
One of the pages said that lower overall dopamine levels are the reason for addictions to drugs. In order to feel as happy as some do naturally, those that need higher dopamine levels must use artificial means. If people could get dopamine injections instead of cocaine, should that be legal ? For people that need a lot of dopamine to get them happy, should a dopamine pill be used? Or, should parents be allowed to have their child's DNA screened to determine before hand what their child's response to neurotransmitters will be and then select accordingly or make alterations ? 4 Is one better then the other?
One of the pages stated that evolution has selected for people that need more dopamine for happiness. They did a study with honeybees and found that the way bees choose to go to the sweetest plants, is similar to a dopamine reward system. If the bees were just happy, then they would go to any flower, they would not discriminate. So, somewhere in history it was more beneficial to be less sensitive to dopamine. While in the modern world you might be more likely to become an addict. Should, as one of the pages mentioned, patches (similar to nicotine patches) that help increase sensitivity to dopamine be given out to the those unhappy people?
In some of my other psychology classes when there is a question, we frequently turn to one method for the answer. No, we don't take out the nervous system and study it, but we look at twin studies. These studies frequently indicate that genes determine a person's personality. Two twin sisters meet and they have on the same outfit, got married to men with the same name, injured themselves at the same place, etc. They both have the same genes but a different I-functions. Still, twins might be so similar because everyone treats them a certain way based on their looks and are thus shaped by their environment. However, I do believe that there is free will and if someone wants to be happy, then they can convince themself that they are happy. I tried to make myself happy one dismal night when I felt sort of depressed. So I started forcing a smile and whistling and soon I was doing it because I was happy.
How do animals fit in with this information. Some animals have personalities, but do they have I-functions? The studies do not seem to fully explain personality let alone the I-function. Some of the researchers do believe that eventually personality will be able to be mapped out from genes, what will this mean to us? How much can individual will power override centuries of genetic determination and a lifetime of environmental molding? Is happiness really that important? I read in a book about bipolar disorder and it said that the great art that has been produced out of misery will certainly remind people that happiness is not everything.
What's Your Type? Meyers-Briggs Type Indicator
Forget Money; Nothing Can Buy Happiness, Some Researchers Say from the New York Times
ADDICTED: Why do people get hooked? Mounting evidence points to a powerful brain chemical, dopamine. by J. Madeline Nash, for Time Magazine
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This paper reflects the research and thoughts of a student at the time the paper was written for a course at Bryn Mawr College. Like other materials on Serendip, it is not intended to be "authoritative" but rather to help others further develop their own explorations. Web links were active as of the time the paper was posted but are not updated.