Where Does Personality Come From? - Discovering the Secrets Our Brain Holds
What Influences Our Personalities?
Where exactly personality comes from still has some mystery to it. Genetics, environment, experiences, all play a big role in who we are, in our behavior and how we react to situations. Science has long studied how biology and genetics influence our physical characteristics. Science has looked for, but never found a personality gene. New imaging machines, have been able to look at various regions of the brain and the wiring within to get a better idea about how personality types react to stimulation from the outside world. Personality traits are influenced by many factors.
The Human Brain and Personality
How we respond to other people is related to our own psychological, biological and genetic makeup. Scientists are learning much more about the human brain and personality through fMRI (functional magnetic resonance imager). Researchers can now accurately see which parts of the brain get stimulated from, how much, from what. Through observation, we can see that an extroverted person is more likely to smile at someone else than an introverted person. With fMRIs, we can now see what is going on in the brain. By seeing specific parts of the brain light up we can see them react and with this, some correlations can be made with personalities. People respond to pleasant things in different ways in large part because of the differences in our personalities.
Observing the Brain Responding
The amygdala, is a part of the brain that usually lights up when a person feels danger or something unpleasant. The amygdala is important to the emotional processing the brain does.
These studies show that are brain and our personality are integrally related.
What our brain likes is what we seek. In a study done on 14 women ages 19-42, their brain reacted to pictures that were shown to them while they were in an fMRI imaging machine. The images were able to record their responses to emotional stimuli (the pictures). Some of the negative pictures showed angry or crying people, guns, a cemetary, spiders. Some pictures that illicited positive images were of cute puppies, a happy couple, brownies, sunsets, icecream. The images provoked emotional reactions that were measured by the researchers to determine their level of extraversion. Those who have the tendency to be friendly and optimistic. They wanted to compare extraverts with shy people. They were also able to observe people’s level of anxiety and insecurity to determine their tendency towards neuroticism. The imaging results showed women who ranked higher on extraversion had more brain reactivity towards the positive photos. There were several areas of the brain that responded to the positive images that related to emotion. The frontal cortex, amygdala and anterior cingulate areas of the brain showed this reaction. In comparing this to the women who scored lower on the extraversion scale, there was little or no brain response to the photos that depicted positive images.
Introverts and Extroverts
For those who scored high on the neuroticism their brain responses to the negative photos showed more activity but it was in fewer parts of the brain that control emotions. It appears that different parts of the brain became amplified depending on the individual’s personality trait. The same photos were shown to all the participants, in the same environment. The only variable was their individual personality. The study is showing that people’s reaction to emotional stimuli are connected to the personality factors that make up the individual. There was another study that was done with extraverted compared to depressed people. Extraverts showed more frontal blood flow, even when they were resting compared to introverted people and depressed people. Those who were found to have more neurotic tendencies had reduced flow in the same area of the brain.
The Mysteries and Complexities of Personalities and the Brain
A study was done with 15 students who were determined to be either extroverted, optimistic and outgoing or neurotic, worried and insecure. None of the participants were in the extreme range. But the purpose of the study was to use people with very different personalities. The students were hooked up to an fMRI and then asked to look some photos. The researchers saw the amygdala light up from all the participants when they were shown a threatening or unpleasant expression. But when they were shown a happy face, the introverted people showed little response. The researchers believe the more of an extrovert the person is, the more their brain will react to a pleasant association. What scientist don’t know yet, is it the personality of the person that makes the amygdala react or is it the amygdala, the brain, telling the person to react that way.
As the mysteries of the brain and the complexities of personalities become more apparent, scientists will be able to use this information towards greater understanding of what makes us human. The amygdala is the area of the brain associated with emotional memories, face recognition, visual processing, and emotional reactions to experiences. Scientists are quite sure how big a role the amygdala plays in all of these things. More studies will be done to determine the relationship between parts of the brain and our personalities. There is more to learn about our memory, experiences, our focus and our perception and how this affects different domains of the brain.
The Wiring of the Brain
The way our brain is wired, the size of different parts of our brain, our experiences, our mental states, our biology, and genetic makeup, the culture in which we live, all influence our personalities.
At the University of Bonn, scientists suggested that the neural connection between different areas of the brain may be more developed in creative thinking individuals. They did a study where participants self described their personality as seeking out new things for fun or challenge, or more of a stay at home type person. They also had to describe themselves as people pleasers or not caring whether other people like them or the things they do to get a feel for the individuals own social acceptance,
The reward center of our brain called the striatum. The hippocampus area of our brain is related to memory. Researchers believe that it is the hippocampus that identifies new experiences and sends this information to the striatum. Neurotransmitters release chemicals in our brain that lead to positive feelings. People who constantly need new stimulation have a strongly wired connection between their hippocampus and striatum. It is very difficult to understand and visibly see the wiring in the brain.Tomography imaging now make this possible. Scientists can determine which direction fluid in the tissue of the brain moves.
Areas of the Brain affect our Behavior
For the individuals who were people pleasers, the study also showed a correlation between the area of the frontal lobe part of the brain and the ventral striatum. The ventral striatum is strongly related to emotions in people. Science has already determined that people who have defects, lets say from a stroke, may violate sociatal norms. These scientists want to conduct more experiments to gain a greater understanding about the wiring in the brain and personality and our behavior.
Where exactly personality comes from still has some mystery to it. Genetics plays a big role. Shy infants tend to be shy throughout childhood.
Personality traits are influenced by many factors. Biology and environmental factors play a big part of a these characteristics. Behavior genetic scientists have used family studies extensively, including twin and adoption research. To understand how the environment impacts a person, they will look at shared and non-shared environment. When siblings grow up in the same family, it is considered shared environments. Non-shared environments are specific and unique to that person.
Some theorists believe our basic personality begins at birth or perhaps even in utero. Shy infants tend to be shy throughout childhood.
The Size of Areas in the Brain and Personality
Intelligence, behavior, personality characteristics and even height do not have a single gene that dictates that person’s specific trait. These characteristics are all inherited, but there are many genes that make create the specific trait. Scientists are looking at the genetic makeup to see how biology influences the personality of people. Experiences combine with biology to play a role in our personalities.
Biology influence a person’s temperament or dispositon, and show our individualized personalities. People’s moods are even thought to be genetic. Scientists believe genetic material influences the nervous system. This can readily be seen in people who suffer from depression and neurotransmitters and serotonin levels. Studies have shown that going through stressful events could cause depression but there was no evidence that it was connected to any specific genes. This is where scientists believe they are better off looking at a group of genes to pinpoint the traits, than to one specific gene. Just as there are many genes involved in influencing personalities, there are many experiences, not just one, that affect personalities.
Other scientists are discovering that the size of the different parts of the brain may be a link to different personality types. They believe that people who are conscientious tend to have a larger lateral prefrontal cortex. This area of the brain is related to controlling and planning behavior.
The Big 5 Factor
A popular personality theory is known as the Big Five (5) Factor. People can be divided into 5 general personality characteristics:
A researcher by the name of Colin DeYoung from the University of Minnesota wanted to learn if the size of the brain structures were related to these personality factors. 116 people answered a questionnaire which described their own personality.
An fMRI brain image was done to measure the size of various parts of their brains. He found several correlations between brain size in certain areas and personality. Extraverts seek reward. There are reward centers in the brain. DeYoung wanted to see if areas like this were larger in extraverted people. The medial orbitofrontal cortex which sits in the area above and behind our eyes was markedly larger in people who are outgoing. The area reacts to rewards.
People who are conscientious are hard working and disciplined. The same held true for areas that related to planning, the people in the survey who had larger areas of this part of the brain were more conscientious. This personality type can plan ahead, and get through complicated thoughts to make decisions. The area of the brain known as the lateral prefrontal cortex was larger than average in people who are conscientious.
Neuroticism is related to negative emotions and sensitivity to threatening situations had larger regions that correlated with this personality trait. Neuroticism relates to depressing and sad thoughts. The fMRI showed they had smaller medial prefrontal cortexes. This area regulates emotion. These negative feelings affect our emotions.
People who were more agreeable in their personality had a larger area that helps them understand another person’s emotions. Having an agreeable personality corresponded to larger brain regions.
People who exhibited a tendency towards openness are creative, open to new experiences, and experience new ways to think of things. Those people in this study who were rated as opendid not have any particularly larger brain structure that was detected by this study.
There is So Much More to Learn
While this study gives us a lot more information, more research still needs to be done. The study of personalities still has a lot more to learn.
This study may show that there are biological factors that influence our personality and behavior. Personality is a complex science. The biological factors are also influenced by our experiences and interpretations. Scientists are well aware that our brain is constantly growing and changing. The biological tendency may make us more predisposed to have a certain personality type, but it does not mean it is fixed from the time we are born. Our brain changes based on outside influences that we encounter.
The complexities of personalities are influenced by nature and by nuture. Our personalities evolve from many influences. Scientists and psychologists are just embarking on the journey to find out more about the brain and behavior, personality and genetics, and the many other influences that influence and control who we are.
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