First of all he points out that:
Introversion is one of a constellation of factors that fluidly work together to shape how we act. Introverts gather the information that feeds our inner worlds in different ways; some rely on the concrete experiences of the senses (an S on the Myers-Briggs), while some depend more on their intuition (an N), interpreting what lies below the surface. Some introverts make decisions more from their hearts (An F) and others more from their heads (a T). Some prefer to structure their lives carefully (a J), whereas others opt for more spontaneity and flexibility (a P).
We also fall somewhere along a spectrum between introversion and extroversion. With the three categories he describes, I find that some people immediately strike me as extroverted in one category, but it's a little more ambiguous in another category. And even within a specific category, we may lean toward one side or another, but it's possible that we show characteristics of the opposite side of the spectrum at times.
The three categories of introversion/extroversion are: 1) energy source, 2) internal vs. external processing, and 3) depth vs. breadth.
Introverts are energized by solitude. We are recharged from the inside out, from the forces of our internal world of ideas and feelings.
We generally fill our energy tanks in private or in the presence of one or two close friends, or else in a public place without interacting with those around us.
Long periods without quiet refueling leave introverts feeling physically exhausted and emotionally hollow.
Extroverts, on the other hand, derive their energy from outside of themselves. They need other people, interaction and various kinds of stimulation in order to replenish their energy. Too much time alone, silence or inactivity leaves extroverts feeling drained.
I've often heard people explain the energy category (and I've done this myself) specifically in terms of spending time with people, but over time I've grown to see that it's not just a people thing. As he points out above, activity and variety are also keys to the energy equation. I've noticed before that on days when I have one large project to work on (like making year end school movies or pumping out year end giving statements) I have more energy at the end of the day than when I've spent the day clawing my way through a to-do list 20 items long (even when the items on the list were all small things like making a phone call or tackling some burnt out light bulbs). There's something about the transitioning from one task to the other that wears me out. If I can find a way to make the tasks all seem congruent, I do better than when they strike me as disparate tasks.
In our culture we are continuously bombarded by stimuli, in the forms of information, images, conversation, and a multitude of other data and experiences. In order for introverts' lives not to degenerate into disassociated states of confusion, we need to process these stimuli and integrate them into our lives. Another way that this integration process might be described is filtering. We need to filter information and experiences, allowing the good to take root in us and transform us, discarding the bad or irrelevant.
Extroverts have flexible and porous filters that allow much to pass without getting clogged. They can usually take a much higher amount of stimuli before they become inundated. They mostly process externally, through conversation and interaction with others. Taking is an integral part of their processing, and they often speak in order to understand. Their speaking and thinking occur simultaneously. Though they are capable internal filtering and reflection, they are most alive when engaged in the world of people and activity.
...extroverts may be more physically expressive than introverts.
The introverted filter, on the other hand, is much finer and more rigid, only able to allow small amounts of stimuli to pass before it backs up. Introverts process internally, in the workings of our own minds. We integrate and think silently. Ideally, we like to be removed from external stimuli and people in order to process.
Though we are capable of engaging in the world, we are most alive in the reflections of our minds, mulling over concepts and experiences. Our learning style centers around observation and contemplation, and we are not as dependent on external feedback for growth.
Many introverts do not do well with interruptions, either when we are speaking or reflecting.
When the finer filters of introverts become clogged in the presence of people, we often go silent.
When this filtration process is impeded, the result can be disorientation and confusion -- or for me, temporary depression....
My first thought upon reading about this second category was, "but I'm so good with Dad!" Part of having Picks disease includes perseveration, which means saying the same thing over and over and over again until everyone around you goes insane. My dad's perseveration drove my mom nuts, and my sister, but somehow I put up with it easily. But I suspect that's because, after having 3 kids under the age of 2, I learned to filter beyond my filter. I could "turn off" my dad in a way that they couldn't and sometimes people would complain about my dad's repetitions and I'd be surprised that he'd been speaking that whole time and I hadn't even noticed. (My kids hate when I've turned them off -- they keep asking me a question and I don't hear them at all. There are definitely times when it's not an asset.)
But as I finished reading this section, especially the last bits about shutting down and getting depressed, a light bulb went off. There have been so many times when I've been in the midst of a stressful conversation and between my trying to convey my thoughts to people who obviously weren't understanding me, and trying to make sense of and sort through their responses to me, I would just get to the point where I couldn't even function any more. I'd have to leave the room. Or I'd break down in tears. Or I would just get very, very quiet.
Introverts tend toward high degrees of intimacy in our relationship, which we usually have fewer of than extroverts. Introverts are rarely content with surface-level relationship and do not generally consider our acquaintances to be friends. We may find small talk to be disagreeable and tiring.
Introverts also prefer to have depth in fewer interests. This trait is connected to our style of processing. The breadth of information about a wealth of topics often results in introverted-filter overload. Instead, introverts prefer to invest our energy resources into a a smaller number of topics or activities. We desire to mine them for all their richness, to explore all their nuances and complexities. This commitment to specialization of expertise, along with our love of ideas and our powers of concentration, explains why many introverts thrive in lives of scholarship.
Although this third category introduces a new idea regarding introverted vs. extroverted behavior, I think it overlaps a lot with the other two categories. Switching between topics is harder on our filters than sticking with one topic and digging deep. The same holds true with switching between activities or even with the number of people we hang out with.
McHugh, in this chapter on the differences between Introverts and Extroverts, gives a list of "common attributes of introverts." If you're still not sure on which side of the spectrum you fall, perhaps this will help:
- Prefer to relax alone or with a few close friends.
- Consider only deep relationships as friends.
- Need rest after outside activities, even ones we enjoy.
- Often listen but talk a lot about topics of importance to us.
- Appear calm, self-contained and like to observe
- Tend to think before we speak or act
- May prefer a quiet atmostphere
- Experience our minds going blank in groups or under pressure
- Don't like feeling rushed
- Have great powers of concentration
- Dislike small talk
- Are territorial -- desire private space and time
- May treat their homes as their sanctuaries
- Prefer to work on own rather than with a group
- May prefer written communication
- Do not share private thoughts with many people