What is a personality? It’s something everyone knows but when we’re held on the point, we find difficult to define. According to the American Psychological Association (APA), “Personality refers to individual differences in characteristic patterns of thinking, feeling, and behaving.” With the Nature vs. Nurture debate, each side has weighed in now and then on how personality is formed. Which is more important has been debated for centuries. 17th philosopher John Locke was convinced that the human mind was a “Tabula rasa” or blank slate at birth, a concept first introduced by Aristotle. It was experience that formed personality, they argued.
According to biological anthropologist Helen Fisher, PhD, personality breaks down into two essential forces, culture and temperament. Culture is how we’re conditioned to act growing up. Temperament is biological. What Dr. Fisher has discovered she calls, “Traits of temperament.” She’s a senior research fellow at The Kinsey Institute, chief science adviser for Match.com, and a research professor at Rutgers University.
Dr. Fisher spent four years digging through the medical literature and examining anything associated with personality. This included studies on genetics, hormones, pharmaceuticals, sexual reassignment surgery, brain architecture, and neurotransmitters. Soon she recognized a pattern. Dr. Fisher found that there was a “host of personality traits linked with four brain systems. The dopamine, testosterone, estrogen/oxytocin, and serotonin systems.”
With the help of a statistician, she took the data and developed a personality questionnaire. She told me in a recent phone interview that, “It’s the first questionnaire in the world that started from the knowledge of neural circuitry and then proven with brain-scanning studies.” It’s also the first to link brain activity to what she calls traits of temperament.
Dr. Helen Fisher. Anatomy of Love.
The four traits of temperament are Explorers, Builders, Directors, and Negotiators. Note that any of these can pertain to a man or a woman. Each temperament has its own traits and is driven by a particular neurotransmitter or hormone.
Explorers are curious and energetic. They’re driven by dopamine—the pleasure neurotransmitter. It gives us a sense of elation, accomplishment, and reward. Pretty much anything that gives us pleasure from food to alcohol to sex gooses dopamine production. Explorers are thrill seekers who are open-minded, creative, and cerebral. They crave adventure and novelty, and are easily bored. They may be impulsive and lack introspection however, as they are forever outward looking.
Builders are cautious. They’re driven by serotonin which gives us a sense of relaxation, belonging, and comfort. They’re sociable, follow the rules, and are respectful. These folks are meticulous, orderly, methodical, good with numbers, and may be religious. They are creatures of habit and practice self-control. Dr. Fisher calls this type “cautious/social norm compliant.”
Directors are driven by the testosterone system. They are honest, confident, assertive, and analytical. As a result of receiving fetal testosterone, they have a tendency to understand math, music, computers or any “rule-based systems.” They also have higher visual-spatial perception, which may make them good at sports. These are detail-oriented. Directors become experts in a certain field, but may not have too many interests beyond that. They may lack empathy or sensitivity, be less verbally astute, less understanding of others emotions, and give less eye contact. They also may prone to being flooded by their emotions, making them prone to outbursts, particularly of anger.
Negotiators received a hearty helping of prenatal estrogen. Estrogen is closely related to oxytocin, the “calm and cuddle” hormone. This type is trusting, generous, imaginative, social, and open-minded. They’re also very nurturing and empathetic. Negotiators have excellent verbal skills. Dr. Fisher calls them, “prosocial/empathetic.”
Explorers are the creative types, mostly expressing dopamine. Getty Images.
14 million Americans have taken the questionnaire via Match.com and Chemistry.com, along with several other thousand people from over 40 countries. To take the quiz yourself, click here. She and a colleague placed subjects in a brain scanner after taking the questionnaire. Say the subject self-identified as a risk-taker who is curious and energetic.
“Sure enough, we put them in the brain scanner, and that whole brain pathway for the dopamine system became very active.” She and her colleague also saw more activity in the ventral tegmental area (VTA), the tiny region at the base of the brain where dopamine is produced. They had similar findings with serotonin. Those who were testosterone driven showed more activity under an FMRI in areas of the brain developed in the womb by fetal testosterone. They saw the same pattern among the estrogen-driven.
Her new research looks into what degree each of these brain systems is expressed in different people. “We’re not all dopamine. We’re not all serotonin,” Dr. Fisher said. “We’re not all a negotiator. We are a combination of all of them. But we express some more than others. And that’s what creates our basic personality.” Another advantage to her questionnaire, besides it being tied to hard science, is the fact that it doesn’t cubbyhole people. Rather, it shows what level of each system they express.
Now, she and a colleague have created a second generation questionnaire called the NeuroColor Temperament Inventory. It’s part of a company she’s started called NeuroColor. It’s based on her first generation work. But this incarnation is “designed to be used in the business community.” She said, “Each of these four broad styles of thinking and behaving…breaks down into two subsystems.”
Two subsets of personality traits can make those who are alike different in other ways. Getty Images.
Subsets of Personality. “A lot of people are both. But not everybody.”
Testosterone System subsets (Directors): Systems-thinking, and tough-minded and direct. Some who express testosterone for instance are system’s thinkers. They’re engineers, mathematicians, or scientists, but they aren’t so tough-minded. Women who are testosterone driven tend to be this way, according to Dr. Fisher.
Estrogen System subsets (Negotiators): Empathetic and inclusive, and contemplative and contextual. “I have found quite a few men who are empathetic and inclusive, but are not contemplative and contextual. What I mean, I'm estrogen-driven. I ruminate. I think over and over. I’ll think about the context. ‘He meant this because of this.’” Men however who are she tends to find, miss the context and don't often contemplate.
Serotonin System subsets (Builders): Prudent and principled, and concrete and methodical. “These people aren’t incredibly interested in theory. They want the facts. They want the details. They want to go step-by-step. They want to be careful. They are not risk-takers.”
Dopamine System subsets (Explorers): Curious and energetic, and inventive and future-oriented. “I know very many people who are very curious and energetic, but they’re not inventive. They’ll read novel after book, they want to go to the opera or the symphony, and they want to travel all over the world. They read poetry but don’t write it.”
Estrogen expressing men tend to be empathetic and inclusive. Getty Images.
Dr. Fisher said, “There’s people like Steve Jobs. I think he was very tough-minded, but I’m not sure he was a systems thinker. He was designing things. But he wasn’t down in the basement writing code. Einstein I think was both tough-minded and direct. So it begins to break down into substyles. And we’re getting much more granular.”
As for future plans, she’ll keep digging and developing a more sophisticated understanding of our temperament. “The future lies in going directly to the genetics, again. We’ve got 63 genes that we want to study.” Though we know some genes related to personality traits, she wants to know the whole combination and how they interact. “We’ll eventually be able to really map personality,” she said.
To take the 1st generation questionnaire yourself, click here.
To learn more about where behavior emanates from in the brain, click here:
- The jaw bones of an 8-million-year-old ape were discovered at Nikiti, Greece, in the '90s.
- Researchers speculate it could be a previously unknown species and one of humanity's earliest evolutionary ancestors.
- These fossils may change how we view the evolution of our species.
Homo sapiens have been on earth for 200,000 years — give or take a few ten-thousand-year stretches. Much of that time is shrouded in the fog of prehistory. What we do know has been pieced together by deciphering the fossil record through the principles of evolutionary theory. Yet new discoveries contain the potential to refashion that knowledge and lead scientists to new, previously unconsidered conclusions.
A set of 8-million-year-old teeth may have done just that. Researchers recently inspected the upper and lower jaw of an ancient European ape. Their conclusions suggest that humanity's forebearers may have arisen in Europe before migrating to Africa, potentially upending a scientific consensus that has stood since Darwin's day.
Rethinking humanity's origin story
The frontispiece of Thomas Huxley's Evidence as to Man's Place in Nature (1863) sketched by natural history artist Benjamin Waterhouse Hawkins. (Photo: Wikimedia Commons)
As reported in New Scientist, the 8- to 9-million-year-old hominin jaw bones were found at Nikiti, northern Greece, in the '90s. Scientists originally pegged the chompers as belonging to a member of Ouranopithecus, an genus of extinct Eurasian ape.
David Begun, an anthropologist at the University of Toronto, and his team recently reexamined the jaw bones. They argue that the original identification was incorrect. Based on the fossil's hominin-like canines and premolar roots, they identify that the ape belongs to a previously unknown proto-hominin.
The researchers hypothesize that these proto-hominins were the evolutionary ancestors of another European great ape Graecopithecus, which the same team tentatively identified as an early hominin in 2017. Graecopithecus lived in south-east Europe 7.2 million years ago. If the premise is correct, these hominins would have migrated to Africa 7 million years ago, after undergoing much of their evolutionary development in Europe.
Begun points out that south-east Europe was once occupied by the ancestors of animals like the giraffe and rhino, too. "It's widely agreed that this was the found fauna of most of what we see in Africa today," he told New Scientists. "If the antelopes and giraffes could get into Africa 7 million years ago, why not the apes?"
He recently outlined this idea at a conference of the American Association of Physical Anthropologists.
It's worth noting that Begun has made similar hypotheses before. Writing for the Journal of Human Evolution in 2002, Begun and Elmar Heizmann of the Natural history Museum of Stuttgart discussed a great ape fossil found in Germany that they argued could be the ancestor (broadly speaking) of all living great apes and humans.
"Found in Germany 20 years ago, this specimen is about 16.5 million years old, some 1.5 million years older than similar species from East Africa," Begun said in a statement then. "It suggests that the great ape and human lineage first appeared in Eurasia and not Africa."
Migrating out of Africa
In the Descent of Man, Charles Darwin proposed that hominins descended out of Africa. Considering the relatively few fossils available at the time, it is a testament to Darwin's astuteness that his hypothesis remains the leading theory.
Since Darwin's time, we have unearthed many more fossils and discovered new evidence in genetics. As such, our African-origin story has undergone many updates and revisions since 1871. Today, it has splintered into two theories: the "out of Africa" theory and the "multi-regional" theory.
The out of Africa theory suggests that the cradle of all humanity was Africa. Homo sapiens evolved exclusively and recently on that continent. At some point in prehistory, our ancestors migrated from Africa to Eurasia and replaced other subspecies of the genus Homo, such as Neanderthals. This is the dominant theory among scientists, and current evidence seems to support it best — though, say that in some circles and be prepared for a late-night debate that goes well past last call.
The multi-regional theory suggests that humans evolved in parallel across various regions. According to this model, the hominins Homo erectus left Africa to settle across Eurasia and (maybe) Australia. These disparate populations eventually evolved into modern humans thanks to a helping dollop of gene flow.
Of course, there are the broad strokes of very nuanced models, and we're leaving a lot of discussion out. There is, for example, a debate as to whether African Homo erectus fossils should be considered alongside Asian ones or should be labeled as a different subspecies, Homo ergaster.
Proponents of the out-of-Africa model aren't sure whether non-African humans descended from a single migration out of Africa or at least two major waves of migration followed by a lot of interbreeding.
Did we head east or south of Eden?
Not all anthropologists agree with Begun and his team's conclusions. As noted by New Scientist, it is possible that the Nikiti ape is not related to hominins at all. It may have evolved similar features independently, developing teeth to eat similar foods or chew in a similar manner as early hominins.
Ultimately, Nikiti ape alone doesn't offer enough evidence to upend the out of Africa model, which is supported by a more robust fossil record and DNA evidence. But additional evidence may be uncovered to lend further credence to Begun's hypothesis or lead us to yet unconsidered ideas about humanity's evolution.
