What Makes Us Introverts and Extroverts?
By John Rieping on October 31, 2012; Updated July 6, 2015
|
|
Are you better at calming yourself down than getting riled up? If so, you may be an introvert. If you're more enthusiastic, perhaps you're an extrovert.
What are introverts and extroverts? My computer's dictionary defines an introvert as "a shy, reticent, and typically self-centered person" and an extrovert as "an outgoing, overtly expressive person." I think it may be more accurate to say instead that a tired introvert frequently restores herself in introspective (often solitary and soothing) activities while a listless extrovert will usually find energy in outward-directed (often social and lively) activities.
But beneath these clumsy definitions lie, perhaps, the answers to a more fundamental question: why?
What are introverts and extroverts? My computer's dictionary defines an introvert as "a shy, reticent, and typically self-centered person" and an extrovert as "an outgoing, overtly expressive person." I think it may be more accurate to say instead that a tired introvert frequently restores herself in introspective (often solitary and soothing) activities while a listless extrovert will usually find energy in outward-directed (often social and lively) activities.
But beneath these clumsy definitions lie, perhaps, the answers to a more fundamental question: why?
WHY ARE SOME PEOPLE INTROVERTS?
According to one theory, the defining genetic trait of introverts may be oversensitivity to dopamine, a feel-good chemical produced by the brain. To oversimplify, excitement produces dopamine. The oversensitivity of introverts to dopamine doesn't mean they can't appreciate excitement. But it does mean that introverts can be fairly easily over-stimulated by too much dopamine being produced. At those times, introverts want to withdraw and let the dopamine levels subside before returning to the stimulating activity. Some research suggests a connection between anorexia and oversensitivity to dopamine. |
|
WHY ARE SOME PEOPLE EXTROVERTS?
Extroversion may be caused by insensitivity to dopamine in the brain. The brain's response is to seek out certain kinds of stimulation that spur dopamine production. It does this by adopting a brain-use pattern that excites the self and sparks activity. This is a stressful strategy. Figuratively speaking it is a hyperactive chihuahua dog who won't stop yipping because it needs you to open the door so it can pee on the grass outside. (Okay, I may be exaggerating with the chihuahua analogy.)
Some research suggests a connection between obesity and insensitivity to dopamine.
INTROVERTS, EXTROVERTS, AND GENETICS
Studies have found that the brains of introverts and extroverts are "wired" differently. To be specific, blood flows in a different path in brains of introverts and extroverts. This difference does appear to be genetic, rather than an acquired trait, and manifests early in life. The D4DR gene in our DNA "affects the neurotransmitter dopamine, which controls excitement levels and is vital for physical activity and motivation." (Marti Olson Laney, Psy.D., "The Introvert Advantage") A long D4DR gene results in less sensitivity to dopamine. A short D4DR gene results in high sensitivity to dopamine. This difference is connected with different behavior that we traditionally associate with introversion and extroversion. That same variance in behavior is associated with different dominant blood flow patterns in the brain. |
|
The extrovert path is relatively short, and is optimized to stimulate dopamine. It would seem extroverts have a long D4DR gene. The extrovert path in the brain is focused on the sympathetic system, better known as the "fight, fright, or flight" system.
The introvert path is longer, and is optimized to economize and store energy. It would seem introverts have a short D4DR gene. The introvert path in the brain is focused on the parasympathetic system, which is a "throttle-down" system and "signals the body to conserve and withdraw."
As a result of this, extroverts generally find it easier to excite than to calm down, and introverts generally are less excitable and prefer tranquility.
ARE INTROVERTS SLOWER THINKERS THAN EXTROVERTS?
As far as quick or slow thinking, it seems that introverts have slower memory recall than extroverts. The path their brain takes when thinking is longer than the one extroverts prefer. Likewise extroverts tend to react more quickly than introverts -- unless the introvert has developed well a particular skill, such as a playing soccer. But an introverted athlete's quick game reflexes, acquired through training, won't necessarily show up off the playing field.
ARE INTROVERTS MORE FAITHFUL TO LOVERS THAN EXTROVERTS?
One study found that a long D4DR gene significantly increased the likelihood of a person cheating on a romantic partner (J.R. Garcia, “Associations between dopamine D4 receptor gene variation with both infidelity and social promiscuity”). However the study report notes that the issue of cheating is more complicated than just one's genes.
HOW CAN I PRODUCE MORE DOPAMINE?
According to a search of psychology articles on the Internet and a quick skim of "The Introvert Advantage" by Marti Olsen Laney, Psy.D., here are some easy ways to get your body to produce more dopamine:
WHAT ARE SIDE EFFECTS OF TOO MUCH DOPAMINE?
Possible side effects of "too much" dopamine production (note that what seems "too much" is different for extroverts and introverts): sleep and digestive problems, heart disease, and deficiencies in the immune system. Sleep problems, such as those caused by "too much" dopamine, and high blood pressure may also increase the risk of Alzheimer's disease.
HOW CAN I PRODUCE LESS DOPAMINE?
Easy activities that reduce dopamine seem to be:
WHAT ARE SIDE EFFECTS OF TOO LITTLE DOPAMINE?
Possible side effects of "too little" dopamine production (what is "too little" depends on whether you're an introvert or extrovert): sleepiness, depression, lack of motivation, impulsiveness, cravings, compulsions, low sex drive, greater risk of seasonal affective disorder, and poor attention.
HOW MUCH DOPAMINE DO I NEED?
Whether you're an introvert or extrovert, the ideal is to produce just enough dopamine -- not too much or too little. The difference is that introverts don't need a lot of dopamine to get the right amount, and extroverts do. So our points of balance are different.
Be that as it may be, it is still possible for introverts to get too little dopamine or for extroverts to get too much. But we introverts tend to be more focused on avoiding over-stimulation and extroverts tend to be more oriented towards dodging under-stimulation. We may be likely to lean to the opposite extreme away from what bothers us most.
EXTROVERT AND INTROVERT TRIVIA
The introvert path is longer, and is optimized to economize and store energy. It would seem introverts have a short D4DR gene. The introvert path in the brain is focused on the parasympathetic system, which is a "throttle-down" system and "signals the body to conserve and withdraw."
As a result of this, extroverts generally find it easier to excite than to calm down, and introverts generally are less excitable and prefer tranquility.
ARE INTROVERTS SLOWER THINKERS THAN EXTROVERTS?
As far as quick or slow thinking, it seems that introverts have slower memory recall than extroverts. The path their brain takes when thinking is longer than the one extroverts prefer. Likewise extroverts tend to react more quickly than introverts -- unless the introvert has developed well a particular skill, such as a playing soccer. But an introverted athlete's quick game reflexes, acquired through training, won't necessarily show up off the playing field.
ARE INTROVERTS MORE FAITHFUL TO LOVERS THAN EXTROVERTS?
One study found that a long D4DR gene significantly increased the likelihood of a person cheating on a romantic partner (J.R. Garcia, “Associations between dopamine D4 receptor gene variation with both infidelity and social promiscuity”). However the study report notes that the issue of cheating is more complicated than just one's genes.
HOW CAN I PRODUCE MORE DOPAMINE?
According to a search of psychology articles on the Internet and a quick skim of "The Introvert Advantage" by Marti Olsen Laney, Psy.D., here are some easy ways to get your body to produce more dopamine:
- Competition/challenges
- Exercise (weights and cardiovascular activities)
- Being actively social
- Visibly strong enthusiasm (such as going nuts at a concert)
- Taking risks
- Being actively inquisitive about others
- Eating poultry, nuts, and dairy
- Sleep deprivation (not recommended)
- Taking amphetamines (not recommended)
WHAT ARE SIDE EFFECTS OF TOO MUCH DOPAMINE?
Possible side effects of "too much" dopamine production (note that what seems "too much" is different for extroverts and introverts): sleep and digestive problems, heart disease, and deficiencies in the immune system. Sleep problems, such as those caused by "too much" dopamine, and high blood pressure may also increase the risk of Alzheimer's disease.
HOW CAN I PRODUCE LESS DOPAMINE?
Easy activities that reduce dopamine seem to be:
- Relaxation/calming down/being calm
- Meditation/prayer
- Drinking alcohol (moderation recommended)
- Smoking or eating marijuana (not recommended)
WHAT ARE SIDE EFFECTS OF TOO LITTLE DOPAMINE?
Possible side effects of "too little" dopamine production (what is "too little" depends on whether you're an introvert or extrovert): sleepiness, depression, lack of motivation, impulsiveness, cravings, compulsions, low sex drive, greater risk of seasonal affective disorder, and poor attention.
HOW MUCH DOPAMINE DO I NEED?
Whether you're an introvert or extrovert, the ideal is to produce just enough dopamine -- not too much or too little. The difference is that introverts don't need a lot of dopamine to get the right amount, and extroverts do. So our points of balance are different.
Be that as it may be, it is still possible for introverts to get too little dopamine or for extroverts to get too much. But we introverts tend to be more focused on avoiding over-stimulation and extroverts tend to be more oriented towards dodging under-stimulation. We may be likely to lean to the opposite extreme away from what bothers us most.
EXTROVERT AND INTROVERT TRIVIA
- DIGESTION: A study in the journal "Perceptual and Motor Skills" has found that introverts tend to have a lower blood pressure, a lower physical activity level, a moister mouth, and more frequent hunger pangs than extroverts. Why would this be so? The reason may lie in the sympathetic system, which extroverts use more often than introverts. This system slows down digestion, saliva, and waste elimination, increases alertness, heart rate, blood sugar, and free fatty acids, and more.
- HUMOR: A study found that extroverts tend to prefer nonsense humor, and introverts tend to prefer humor that resolves an incongruence.
- PAIN: Researchers have found that extroverts complain more often about pain than introverts. This would give the natural impression that extroverts have a lower pain threshold. But when that was tested the opposite was found to be true. Extroverts have a higher tolerance to physical pain than introverts. Introverts just don't voice complaints about pain as frequently.
- SLEEP: Studies suggest introverts have more sleep problems than extroverts.
- TIME: Researchers have found that extroverts tend to adapt more quickly to time zone changes than introverts.
For more writings on personality, CLICK HERE.
What Makes Us Introverts and Extroverts? by John Rieping is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.