chapter 1

The Science of Temperament

“Temperament—what does that even mean? I just know that I am shy and quiet. It isn’t something I think about. It is just part of who I am, something I accept as being me.”—Hiro, Age 15

Personality and temperament—two words that have come to be used interchangeably in our culture, but words that have significantly different meanings. Defined by Dictionary.com as being a collection of behaviors that form a person’s character, personality is often influenced by both environmental considerations and things we experience in life. Temperament, on the other hand, is defined as being the traits affecting behavior that a person has at birth. It is shaped by biology and remains relatively unchanged throughout life.

Let me give you an example from my own life. When I was young, I was shy and reserved. I hated the first day of school, hated going someplace new, and struggled when I had to perform. However, my interests included music, dance, and modeling—every one of which required me to do something in front of an audience. These interests mandated that I get over my fear of performing in public. And I did. As an adult, I no longer fear being in front of large groups of people. I find comfort in speaking in front of hundreds of people at a time and no longer struggle with being the center of attention.

But I still get anxious when trying something new. I still consider myself reserved. And I continue to develop a little nausea at the thought of attending a conference with unfamiliar people. That part of me will never change.

So what’s the difference between the two? Why has one aspect of me changed but the other one has not? It is the difference between personality traits and my temperament.

The fear of performing relates to my early feelings of being shy, something that changed through practice and experience. It is, or was, part of my personality. On the other hand, the continuing feeling of apprehension when confronted with something new is part of my temperament. It hasn’t “matured” out of my behavior because it is a natural aspect of who I am. It is part of my hardwiring.

Personality and temperament. Nurture and nature.

Where do the concepts of extroversion and introversion fall into this mix? Often defined by specific behavioral characteristics (outgoing, social, and popular for extroverts, and quiet, shy, and reserved for introverts), these two concepts have long been accepted as part of a person’s personality (Thompson, 2008). Popularly used by psychologist Carl Jung in the 1900s, these terms have found their way into nearly every discussion of personality, from Freud’s somewhat negative view that introversion relates to narcissism, to Cattell’s more neutral inclusion of extraversion and introversion as part of his 16 personality factors (Cattell, Eber, & Tatsuoka, 1980). Personality tests, including the Myers-Briggs Type Indicator and the Minnesota Multiphasic Personality Inventory, regularly include measures for extraversion (another spelling for extroversion) and introversion, using their scales to differentiate temperament in some way. Clearly, psychologists have recognized extroversion and introversion as aspects of temperament and personality throughout modern psychology. But it is the advancements in the field of neurobiology that has yielded the largest gains in our understanding of the field.

Jung (1971) long suspected a biological connection, believing that extroversion and introversion were things that related to how a person interacted with the world at a primal level, and not simply a by-product of the experiences a person has had. He believed that extroverts and introverts fundamentally viewed the world differently, with extroverts seeking stimulation outside of themselves, and introverts seeking internal stimulation.

Further evidence of a likely biological connection in the formation of temperament came from Segal’s (1999) research on identical twins. After studying groups of twins raised apart, startling similarities were indicated with regard to temperament, regardless of the differences in environments in which the twins were raised (Segal, 1999).

Eysenck (1967), too, believed that temperament was a matter of biology. He believed that the differences between extroversion and introversion lay in the brain chemistry systems involving arousal and inhibition, with extroverts relying more heavily on arousal for balance and introverts being inhibition dominant. Although advancements in neuroscience have shown his work to be incomplete and somewhat oversimplistic, Eysenck’s speculation that extroverts and introverts differ with reference to optimal level of arousal and reaction to environmental stimuli is basically correct.

Some of the most powerful research to recently address temperament and extroversion and introversion comes from Kagan’s work (Kagan & Snidman, 2004) with highly sensitive children. In this research, Kagan studied brain chemistry and the role of neurotransmitters on temperament. He postulated that a child’s genetic code determines how neurotransmitters are used and that this preference in the brain was intrinsically linked to temperament (Kagan & Snidman, 2004).

Perhaps the best understanding of the science behind temperament is explained by Marti Olsen Laney (2002) in The Introvert Advantage. Using the work of Kagan, as well as the neurotransmitter research conducted by Hobson, Kosslyn, and others, Laney (2002) described the differences between extroversion and introversion as being a matter of energy usage. Extroverts, Laney explained, use energy widely, while introverts are more likely to conserve it. Laney goes on to cite both the use of neurotransmitters as well as the activation and utilization of the sympathetic and parasympathetic nervous systems as linked to extroversion and introversion.

Now, before you feel like you just woke up in the middle of your college biology class, I have no intention of repeating what Laney so elegantly explained in The Introvert Advantage. Instead I want to focus on what the recent research may mean for you, and, more importantly, for your children.

The chart in Figure 1 summarizes the work of Kagan, Laney, and others and shows at a glance just how different the hardwiring is for extroverts and introverts. It’s no wonder neither group can fully understand the other—they are biologically different in their approach to life.

Figure 1. Extroverts and introverts: A difference in biology.

 

The Biological Differences Between Extroverts and Introverts

This chart shows a few of the biological and resultant behavioral differences between extroverts and introverts.

	Extroverts	Introverts
Neurotransmitter preference (Laney, 2002)	Dopamine—short and quick release system	Acetylcholine—long and slow release system
Arousal pattern	Seeks stimulation from the environment	Seeks stimulation through inner thoughts
Energy usage	Renews energy through connections and activity	Renews energy through internal thoughts and solitude
Nervous system activation (Laney, 2002)	Sympathetic (“fight or flight”)—Promotes activation of the adrenal system in preparation for action.	Parasympathetic (“rest and digest”)—Promotes the synthesis of glycogen and digestion.

Brain chemistry controls how we behave in various situations. The research discussed in The Introvert Advantage points to something Jung (1971) had speculated about so much earlier—extroverts and introverts do, in fact, process energy differently. Extroverts focus on social connections and action as a path toward balanced brain arousal, while introverts look inward, preferring internal thinking as a path toward balance (Laney, 2002). It’s something we are born with, and although we may find ways to neutralize the more extreme aspects of our temperament, at least where extroversion and introversion are involved, I believe we are largely dominant in one or the other.

So what’s the main take-away here? Temperament is a function of nature. And the attributes of extroversion and introversion, as aspects of temperament, are the result of biology. They both have advantages and disadvantages. Although the negative aspects of either one can be mediated through some environmental and behavioral changes, the basic attributes of extroversion and introversion will remain true for you and your children throughout your lifetime.

Think back to the example I gave you of my own life. Although I have learned to overcome my childhood shyness when it came to performing and speaking, my natural reservation at trying something new and the apprehension I feel when starting an unfamiliar task will never disappear. It is part of my hardwiring.

In the next chapter, we’ll examine the actual attributes of extroversion and introversion, as well as some of the problems that can arise with both when we are not in balance. But before we dive into that, I want you and every member of your household to complete the worksheet on page 10. Designed to help you identify the dominant temperaments of every member of your family, this is not a scientifically designed rating scale, but rather a collection of questions designed to help you determine where your innate traits may lie on the continuum.

WORKSHEET 1

 

Understanding My Child’s Temperament (and My Own)

Directions: Read each of the 20 statements and determine if you agree, disagree, or neither. Complete the worksheet for each member of the household, including yourself. If your children are old enough, have them complete the worksheet as well as compare your results.

	I agree	I disagree	I neither agree nor disagree
1. I like talking with people after a long day.
2. I prefer to spend time alone or with few friends.
3. I get sad when I am alone for too long.
4. When I make friends, I make deep friendships.
5. I usually act first, and think second.
6. I prefer to observe new situations before participating in them.
7. I am very talkative.
8. I need to feel comfortable before I will share information with people.
9. I get hyper after fun activities.
10. I typically think before I act.
11. I have no problem talking with strangers.
12. I really “faze out” when I am around large groups for too long.
13. I appear to have a lot of energy.
14. People say I often start talking in the middle of my thoughts.
15. Most people think I have a lot of friends.
16. I listen more than I talk.
17. I don’t like it when things are too predictable.
18. I share my deepest fears with few people (or no one)
19. I love going to parties and hanging out with friends.
20. Being creative is important to me.

Take a look at your answers. The even statements usually relate to introversion, the odd to extroversion. Looking at the chart, where are you dominant? It is important to note that these statements reflect general predictors of temperament. Most people will not fit neatly into a temperament label. Some extroverts may enjoy solitary activities like reading, while some introverts may thrive in the performing arts. Use these statements as guidelines to help you determine which side of the extroversion/introversion coin applies to you and your children the majority of the time. Repeat this for each of the members of the household. Any surprises?

Class Notes: Recognizing Temperament in the Classroom

You’ve all seen it before, the differences in the students in a typical classroom. Some will volunteer answers readily and love to participate in group activities. Others act as though a group project is a death sentence. As an educator, you know that you need to tailor your teaching to meet the needs of your students, coaching the quiet kids to speak out more and teaching the talkative ones to allow others to speak. It’s a balancing act, to be certain.

In current Western educational institutions, collaboration and group activities have become the norm, the “best” type of learning for our students. You know that some of your students don’t thrive with that structure of learning; maybe you’ve even found ways to accommodate them. But the message in education is clear; students need to learn how to work in teams. After all, our modern culture demands this of us.

But how does the introvert fit into this picture?

This chapter has focused on the biological differences between extroversion and introversion, highlighting a fundamental difference in how these two temperaments approach their interactions with the environment. As an educator, it is time to take this information and apply it to the classroom, understanding that the shy child who is reluctant to join groups, no matter how much you encourage him, may not be just “shy.” He may be hardwired differently and require a different approach to learning.

More on that later in the book.

For now, I want you to take the information in the chapter and apply it to the classroom, using a similar worksheet to the one for parents as a way to recognize and identify temperament in your classroom (see p. 13). Use it with any student and enhance your ability to tailor some of your methodologies to the students in your class. Use it with yourself to more deeply understand why you may be energized and/or drained at the end of the day.

TEMPERAMENT Q&A

After reading about the physiology of temperament, you likely have a few questions. Trust me, you are not alone. Here are some questions frequently asked in my focus groups and workshops whenever the subject of temperament is mentioned.

WORKSHEET 2

 

Understanding My Students’ Temperaments (and My Own)

Directions: Read and think about each of the 10 statements as they relate to your students. Complete one worksheet for each student. Or have your students complete it for themselves.

	I agree	I disagree	I neither agree nor disagree
1. I like talking with people after a long day.
2. I prefer to spend time alone or with few friends.
3. I like to volunteer in class.
4. It takes me a while to warm up to a new teacher or a new class.
5. I usually act first, and think second.
6. I prefer to observe new situations before participating in them.
7. I am very talkative.
8. I need to feel comfortable before I will share information with people.
9. I get hyper after fun activities.
10. I typically think before I act.

Take a look at the answers. The even statements related to introversion, the odd relate to extroversion. Remember, these are just general predictors. Most students will have attributes of both temperaments. Use the chart to assess your students’ temperament trends and assist in assessing needs. Looking at the chart, where are your students dominant? Do this for the majority of your students. If you are like most environments, you will find a higher number of extroverts in your classroom. What have you learned?

You stated that introverts and extroverts are hardwired differently. Is this something that can change over time, like with age?

Yes and no. Like anything with our physiology, there are seldom easy answers. Everything is a balance between our hardwiring and our learned patterns of response.

I believe we have a predisposition toward a specific pattern of responding to our environment. In the case of an introverted person, he may always have a physical reaction when asked to answer a question in class or when put on the spot in a business meeting. He may also prefer to think through a problem before acting on it. He may always appear to be tired or “tuned-out” when in crowds for extended periods of time. But how he responds to those initial reactions is likely to change over time. Whereas he may have responded to being in a crowd or being called on in class by withdrawing, being quiet, or becoming physically ill when he was a child, now he responds by taking a deep breath, clearing his thoughts, and talking himself through his feelings. He appears to have minimized his introversion. In fact, the introversion hasn’t changed at all. It is merely his reactions to his biology that have changed over time.

Can someone be both extroverted and introverted, depending on the situation?

There are some psychological studies that have utilized the term ambivert to refer to persons who reflect both extroverted and introverted qualities. They are in the “middle” of the continuum between the two. Before you run off and decide this applies to you, I want to offer you a different opinion. I believe, like Jung, that all human beings possess qualities of both extroversion and introversion. But I also believe that we have a dominant temperament related to our brain chemistry, our use of the autonomic nervous system, and our reaction to various neurotransmitters. In that respect, I would say “no,” you are not extroverted or introverted based on a given situation.

So how do you figure out what is dominant for you or your children? Think back to a time when you were emotionally spent. What did you crave in that moment? Solitude? Time to think, process, or reflect? Or did you want to talk with a friend? Go to a social activity? Run and be active? The answer to these questions can help you determine your dominance—introversion or extroversion.

Is it possible to be too introverted?

Like any aspect of being, too much of something is often not a good thing. When introverts are overwhelmed and out of balance, they have a tendency to fully withdraw from the world. They can become distant, appear unmotivated to complete preferred tasks, and even seem depressed. Their biology, the parts related to introversion, are overactivated, resulting in brain chemistry that is out of sync. The same can happen when an extrovert becomes overstimulated by her dominant brain chemistry, resulting in myriad health problems related to an overexcited stress response.

The key to all of this is learning how to balance the dominant neurology, thereby avoiding the potential pitfalls. I will speak more to this throughout the book, including tips for helping introverted children avoid becoming out of sync.

The chart really clarifies the biological differences between introverts and extroverts. Are there some physical indicators that you have noticed personally that informed you of your temperament?

Ah yes, my personal dealings with my biology. I think the most prominent physical indicators of my introversion come when I am experiencing some form of overload—when the noise and demands of the environment surpass my immediate coping strategies. I literally feel like someone is raking 9-inch nails down my arm when I am overwhelmed. My skin hurts, my ears pound, and I literally can’t think. I can become short-tempered and overly quick to react in a negative way.

I have come to realize that this physical reaction is related to anxiety and stress—both of which are more likely to occur when my system is taxed related to my introversion. Some of the other behavioral characteristics of introversion are covered in the next chapter, as we discuss the specific attributes and characteristics of introversion.

As I am a teacher, I find this information interesting, but not necessarily helpful. How can I use the science of temperament in my daily functioning as an educator?

Understanding temperament can not only enhance your understanding of your students, but can change both your approach to teaching and your understanding of the behavioral nuances you see in your class. The child who refuses to answer questions aloud or stares off into space whenever the noise in the room gets a little louder is no longer a student who is disinterested in learning, poorly motivated, or even learning disabled. Armed with this information, you can now see that the student may, in fact, be hardwired in a way that is contradictory to your class environment or teaching strategies. This understanding will enable you to probe a little deeper and try a few different environmental changes before assuming the student struggles with learning or motivation.

The most important thing the information in this chapter can give you is the gift of tolerance. With a broad and accepting lens, you can view the student’s behavior in a more neutral light, understanding that the behavioral nuances you are observing are not just a choice the student is making, but so much more. And that can make a world of difference for the child.

In the following chapters, I will go more deeply into the actual differences between extroversion and introversion. Until then, try your hand at beginning to recognize the subtle differences yourself.

 

In a Nutshell …

Big Ideas

❖ Temperament is a matter of hardwiring.

❖ Extroverts and introverts respond differently to external and internal stimuli.

❖ Extroverts and introverts utilize their autonomic nervous system differently.

❖ Extroverts and introverts use and react to neurotransmitters differently.

❖ Temperament is only one aspect of who we are. Neither extroverts nor introverts are exactly like one another.

Supplemental Pages

❖ Figure 1: Extroverts and Introverts: A Difference in Biology—page 9

❖ Worksheet 1: Understanding My Child’s Temperament (and My Own)—page 10

❖ Worksheet 2: Understanding My Students’ Temperaments (and My Own)—page 13