Janus was a Roman god of complex qualities. Most commonly, people have viewed him as looking forward to the future and backward to the past. He was known as the god of transitions, of war and peace, of doorways entering and exiting, of gateways and harbors, of passages for both trade and travel, of conflict, of birth and death. Wikipedia has an informative entry on this hard-to-pin-down ancient deity. I like the image at left that depicts Janus on the one hand facing the sunlight, and on the other facing the night. I further complicate the Janus construct, suggesting that his two-headedness serves as a metaphor for extraversion and introversion. From this perspective, extraversion is associated generally with more comfort around sensory bombardment—here suggested by facing the light, while introversion is associated with a preference for relative absence of sensory bombardment—here suggested by the absence of light.
A recent study by Brown University researchers Tara White and Erica Grodin was popularized by the PsyBlog. Scientists claimed to have “discovered” that extraverts come in “two different types.” One nurturing, or affiliative, and one fixed on achievement, or agentic. They associate different brain areas with these two dispositions, both of which harken back to the 1950s writings of Timothy Leary at Harvard.
Well, of course there are two kinds of extraversion! Better said, there are hundreds of kinds of extraversion, each with its own brain system and other physical distinctions. In truth, if you combine extraversion with any one other personality trait, that gives you new paired kinds of extraversion:
- Extraversion + high organization = a neat extravert
- Extraversion + low organization = a messy extravert
- Extraversion + high agreeableness = a nurturing extravert
- Extraversion + low agreeableness = a hard-driving extravert
- Extraversion + high openness = a head-in-the-clouds extravert
- Extraversion + low openness = a feet-on-the-ground extravert
And then we could combine more than three traits:
- Extraversion + low agreeableness + low openness = a competitive extravert with minimal need for variety in life.
Or even more:
- Ext + high openness + math skills + altruistic values + linguistic ability + high energy level = a missionary using advanced analytics to solve logistical problems in underdeveloped countries
In short, thousands of combinations of qualities with extraversion at their core populate our globe. Similarly, introversion comes in thousands of varieties. For every kind of extravert, a parallel introvert exists. The Brown University scientists found the brain areas associated with extraversion and high agreeableness, in contrast to the brain areas associated with extraversion and low agreeableness. The same would be true for introversion: introversion + high agreeableness = the quiet madonna, while introversion + low agreeableness = the quiet mastermind.
To complicate matters further, each of the qualities we’ve mentioned—extraversion/introversion, math ability, altruism, organization, imagination—defines a continuum. An individual’s placement on any given continuum can be understood as being more towards one end, more towards the other end, or somewhere more in the middle—as in more extraverted (an extravert), less extraverted (an introvert), or moderately extraverted (an ambivert—like Janus, who comfortably switches perspectives from extraverted to introverted, like a teacher who spends eight hours in a stimulating environment, then another eight in quiet, solitary study).
At the Center for Applied Cognitive Studies, we refer to these combinations of qualities as “blends.” Humanity comprises millions of unique blends. And, each of these thousands of blends has its own, unique brain, or physical, system.