Q: Recently I hired two part-time assistants. It turns out they are as opposite as night and day. The female is always on the move, the quintessential risk taker. The male is good at what he does but would prefer reading a book in the break room during lunch compared to even walking around the block. Go figure!

A: Go figure is right! These individuals may be at very different positions on the E:I Continuum. An extravert can be as different from an introvert as night is from day. You may have one of each.

PET Scans have shown that behavioral differences may result from using different brain pathways that influence where the individual directs his/her focus-internally or externally.

Work by Dr. Debra Johnson, for example, has shown that brain blood-flow rates differ in extraverts versus introverts.

Extraverts tend to have lower rates of blood flow to the brain, while introverts tend to have higher rates of blood flow to the brain (which goes along with higher rates of internal stimulation). Here are a couple more examples:

Extraversion:

  • Shorter, fast-acting, and less complicated blood flow patterns involve brain areas related to sensory processing (except for smell), variety and novelty
  • Dominant pathway is activated by dopamine, a brain chemical that is implicated in most, if not all, addictive behaviors. Adrenalin, amphetamines, and cocaine have all been found to increase dopamine levels

Introversion:

  • Longer, more complex blood flow patterns involve brain areas related to internal experiences (e.g., planning, pondering, remembering).
  • Dominant pathway is activated by acetylcholine, a neurotransmitter that affects one's alertness and ability to pay attention.

In general, our society does not reward introversion. Because of that, extreme introverts can experience a great deal of pressure to exhibit more extraverted behaviors and can perceive themselves as deficient in some way. They can actually feel like misfits! Understanding this can help you to understand your employees in a way that honors their innate differences.