The Case of the Itchy Amygdala, Part I


synapsesImagine sitting alone in silent utter darkness, trying to make sense of the world when the only clues you receive are bursts of electrical and chemical signals. Was that latest burst a good message or a dangerous one? You fire back a response, and evaluate the results. Did that make you safer? Happier? Or did that make things worse? Slowly, bit by bit, you tease out which signals mean what, and which responses give you desirable results.

That, in a nutshell, is what happens in the baby brain—actually, in all brains. This formidable-yet-fragile organ is cloistered in the cranium for its own protection, unable to have direct contact with the world.
Tofu(Just imagine being a blob of tofu on the loose, and suddenly, being locked up snugly in a skull doesn’t sound so bad.) Everything your brain knows about life it learned from the stimuli intercepted by the rest of the body and routed up through various neural pathways.

Your brain’s earliest responses to those stimuli are initially programmed by basic biology (genetics), and are pretty quickly shaped by the environment, as well (epigenetics)—even in utero. Because infants are non-verbal, there’s no point in asking them directly to report on their emotional state or describe how they are feeling. At this stage, the baby brain’s repertoire of responses is limited to physical actions; it can tell the arms to wave, or the eyes and voice to cry. It can direct the eyes to look at a particular spot, and hold attention for a short time or a longer time.

Scientists have learned to track and measure these outward behaviors as visible signs of what’s going on inside the depths of the brain. Psychologist and researcher Dr. Jerome Kagan stands at the forefront of investigation into the biological roots of Jerome Kaganpersonality, and is considered one of the most influential psychologists of the 20th century.

Kagan has spent decades exploring the nature and source of individual temperament. The Oxford Dictionary defines temperament as “a person’s or animal’s nature, especially as it permanently affects their behavior.” Similarly, Merriam-Webster explains it as “characteristic or habitual inclination or mode of emotional response.”

In his book, The Temperamental Thread (2010), Kagan explains that he and numerous other researchers are working to determine how babies’ brain anatomy and biological conditions shape their life-long emotional responses, self-development, and approach to life. To do this, they began by observing, categorizing, and labeling infants’ physical behavior in response to various stimuli.

ice cubeImagine a researcher coming at Baby You with a piece of ice. When that nasty cold cube comes into contact with your chubby cheek, you will typically have one of the following four reactions to this minor discomfort:

  • Cry lustily, and keep on crying even when cuddled
  • Cry lustily, but calm down quickly with a little cuddling
  • Cry softly, and keep on crying even when cuddled
  • Cry softly, but calm down quickly with a little cuddling

In addition to the above four types of response to discomfort, Kagan found another four patterns in infant reactions to stimuli that are startling, but not actually painful or frustrating (aka novel events). Baby You would do one of the following, upon seeing
assorted unfamiliar objects being gently waggled before your eyes:

  • Move energetically and cry frequently—called the high-reactive response
  • Move energetically and cry rarely
  • Stay still and cry frequently
  • Stay still and cry rarely—called the low-reactive response

Still other patterns of behavior are revealed by responses to frustration, and by spontaneous babbling, smiling, and waving when there are no visible stimuli. Kagan posits that infants probably have somewhere between 15 and 23 fundamental patterns that form the basis for temperament.

So far, this all sounds like Basic Research 101: make observations and categorize results.  Ho-hum. But here’s where Kagan’s work gets really sexy!

He hypothesized that he could look at an individual infant’s response to a novel event and make accurate predictions about the personality of that individual as an adult.

Let’s say that Baby You consistently exhibited a high-reactive Stuffed toyresponse to a novel event. Whenever an investigator gently moved a new stuffed animal above your crib or gave you a whiff of rubbing alcohol on a swab, you wriggled around vigorously and howled loudly to express your feelings about these unfamiliar experiences. Based on these observations, Kagan could predict with statistically significant reliability whether the Adult You would be an introvert or an extrovert.

Place your bets—which result would you imagine to be true:       High-Reactive = Extrovert   —OR—   High-Reactive = Introvert?

For now, I will leave Adult You in suspense. But be patient. All will be revealed in the next post!


Awww–a Bouncing Baby Brain!

Babies intimidate face

Other than having been one a loooong time ago, I have no experience with babies. And I’m morally certain that even if I didn’t drop it, I would not be able to keep up with what goes in one end and out the other. Of course, nurturing that bouncing baby’s brain is probably the most daunting challenge/thrilling opportunity when it comes to bringing up baby.

Intimidating though babies may be, every Self starts out as one. Remember Axiom #1, Self-Awareness: you experience and explain the universe from your own unique perspective.  To understand how that unique perspective is formed, you need to be conversant with the fundamental processes that shaped your baby brain into the YOU of today that you know and love.

As asserted in an earlier post, my simplistic model for human personality development inevitably starts with biology. Over time and through direct experience, you construct beliefs about how the Layers of Selfhood V01world works and your place in it. Eventually, the Self matures enough to further develop through indirect experience; that is, by “borrowing” knowledge by interacting with other humans—either live or via other means of communication, including experience captured in books. Hence my 3B Model for brain-building: Biology→Beliefs→Book-Learning. Let’s see what this process actually looks like, from the perspectives of neuroscience and psychological research.

Your to journey to Selfhood began when the collision of sperm and ova sparked an explosion of developmental activity. His genes plus her genes plus the surrounding environment ultimately delievered You, a unique being, full of potential. And the essence of the real You resides squarely in your brain.

Brain development MRIsAt birth, a baby’s brain is about one-third the size of an adult’s brain. In a mere 90 days, the organ expands to nearly 55 percent of its final size, according to the Journal of the American Medical Association. Authors Aamodt and Wang, in Welcome to Your Child’s Brain  (2011), liken the brain-building process to that of building a house and putting in the wiring: “getting the signaling cells, called neurons, into their correct positions is the (relatively) easy part, and it’s done before [you are] born. In contrast, wiring up all the connections is so complicated that the job won’t be entirely finished until [you are] in college.”

That initial brain-building unfolds in an orderly fashion, prescribed by eons of evolution, encoded in the genetic materials (aka genome) contributed by your parents. Indeed, part of what makes You unique is this specific pairing of parental DNA, genes, and chromosomes. But if you have biological siblings, you and they presumably start out with the same parental genetic inputs, and yet still end up with different personalities and physical features. Even the most identical of “identical” twins are unique individuals. How can this be?

Gregor MendelWhen the monk in the pea patch, Gregor Mendel, laid the groundwork for the science of genetics, he saw the patterns of inheritance as deterministic. The dance steps of development initially seemed totally predictable. Cross pollinate a pea plant that always yields yellow seeds (dominant) with one that always yields green seeds (recessive). The first generation will be all yellow, but you can rely on the second and subsequent generations to produce a 3:1 ratio of yellow to green. Wash, rinse, repeat. The reliability of this cycle formed the initial basis for understanding heritability.

Subsequent researchers, starting primarily with Conrad H. Waddington in the 1930s and 1940s, have pushed beyond this simple model to see that nature choreographs an elegant, endless interplay of interactions between genes and their environment. The presence or absence of specific elements in the environment at any point in your life affects how the dance will flow.

Dancing feetMetaphorically, your genes have specified that you will have two feet, but it’s the ballroom and music surrounding you that determine whether you are doing the tango or the Texas two-step at the moment. Research into this constant conversation between genes and environment is formally called epigenetics.

Our growing understanding of epigenetics has finally put to rest the old argument about nature vs. nurture: it’s both/and, not either/or. Instead of your DNA functioning as a static blueprint for building the DNA strandsedifice known as You, it dynamically responds to external conditions that turn off or turn on various genes. This happens at any point—at many points, actually—throughout your life. In fact, environmental factors in your parents’ lives before you were born affected which of their genes were active, and that, in turn, affected the genes you inherited.

In summary, while you do inherit your genome (i.e., all your combined genetic material), the genome alone does not determine exactly what kind of person you become; however, it does define the range of possible developmental outcomes open to you (Aamodt & Wang, 2011).

In the next post, we’ll explore further this tie between anatomy and attitudes, and try to understand how biology blooms into personality. Stay tuned!