The Highly Sensitive Person

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Back to Comfort ZoneFebruary 2006: Comfort Zone ONLINE
Reflections on Research:
Ignored No Longer: New Interest in Us, New Theories about Us

Science is coming closer and closer to "getting us." Our own research, in collaboration with experts in genetics and brain imagining, has yielded exciting results. However, we are repeating those studies with larger numbers so they can't be discussed yet. Hopefully I can at the next HSP gathering, April 6 through 10 in the U.K. (See for details.) Meanwhile, I know some of you are interested in all aspects of the scientific side of high sensitivity, so I want to tell you about some important new developments. They are a bit complicated, however. My problem is going to be expressing things simply enough for those with a non-science background, without insulting those with one. But let's give it a try.

A Review of the Two Systems--BIS and BAS

In The Highly Sensitive Person I talked about the Behavioral Inhibition System (BIS) and the Behavioral Activation System (BAS) in the brain. The BIS is said to cause us to pause to check the situation, moment to moment, as it changes, to see if it is dangerous or rewarding. HSPs seem to have a strong BIS. It was given this name because it can inhibit behavior for a moment, while more information is gathered, or for longer or entirely, depending on what is encountered. Alas, "inhibition" makes it sound like having a strong Behavioral Inhibition System means having a trait of inhibitedness, anxiety, or neuroticism rather than a trait of keenly observing. Hence I have always maintained that the BIS should be renamed to match its function and be called the Pause-to-Check System.

The BAS does the opposite, in that it leads to the desire to move forward right now--to explore and try to gain good things. You might call it the accelerator. People strong in the BAS are high sensation seekers (HSSs). HSPs can also be HSSs, since the two systems are independent. What makes an HSP/HSS different from an HSS who is not an HSP is that the HSP/HSS enjoys new things, but only if there are not too many risks involved.

I've talked about having both traits elsewhere, mainly in the first chapter of The Highly Sensitive Person in Love, where there's a test for sensation seeking. There are also two excellent articles on being an HSP/HSS in the paper Comfort Zone, Vol. 6 Issues 1 and 2, partly written by an HSP/HSS. I'm also now thinking I should write about it again in the next issue!

So if the BAS is the accelerator, I sometimes say that being an HSP and an HSS is like operating with one foot on the gas, one foot on the brakes. But that's not quite right. The HSP part of an HSP/HSS is not the brakes. It's more like the brains of the driver, checking to see if it's safe to accelerate, to go ahead, get to the goal, or is it time to put on the brakes. Sometimes we brake while we decide, but the BIS is not the brakes itself.

If I call the HSP half the driver, it's not fair to make the HSS just an accelerator, a piece of machinery. So maybe they're both drivers, or one's a back seat driver saying, "Let's go, faster, faster--I want to see what's around that turn." The HSP responds, "Yeah, I know about your curiosity, but no way I'm risking a ticket. And I slow down for curves."

It can be very, very difficult being high in both traits.

How the BIS, and HSPs, Came to Be Associated with Fear

It was Jeffrey Gray who first described the BIS and BAS, back in 1982, in an article entitled "The Neuropsychology of Anxiety." The BIS, according to his theory, consisted of the parts of the brain affected by anxiety-reducing medications. It was a brilliant idea to look at all the parts of the brain affected by a given drug and then consider them as a system and what function they serve. And it seemed obvious that the parts of the brain affected by anxiety medications must be about fear and recognizing threats. Simple. (The BAS was then theorized to have to exist, and dopamine was the neurotransmitter known to have to do with rewards, so they used drugs that specifically suppressed or increased dopamine, noted which parts of the brain responded, and called those the BAS.) Thus Gray's theory fueled the idea that the underlying innate trait of those with a high BIS is anxiety, neuroticism, obsessiveness, or whatever--not sensitivity.

Alas, psychologists who were not brain experts got busy and created a questionnaire that was supposed to identify those with a strong BIS and BAS, thinking correctly that these two types would be due to a very basic biological difference. Unfortunately they focused on the two traits as "withdraw" versus "approach" (not even inhibition versus approach), which came to be seen practically as fear versus joy, pessimism vs. optimism, negative emotions versus positive ones, so forth. You may as well make the traits "spoil-sport-scaredy-cat" versus "fun-to-be-around." And the measure worked. It predicted behavior. People high on withdraw want to avoid risk, as all HSPs do. But the items on the questionnaire were limited to those that asked about avoiding risk and the like, so that it made the trait seem like anyone with a strong BIS wants to withdraw from all risk at all costs.

Why did the questionnaire survive scientific scrutiny? Because there are plenty of HSPs who have had frightening, stressful, traumatic experiences and thus when they "pause to check," they really are fearful, pessimistic, withdrawn, and all the rest. So the questionnaire identified enough fearful HSPs, people with a strong BIS plus traumas, for them to conclude that the trait was about fear. Why not? That's what Gray's article was about.

This measure has become a big deal in psychology--it's used in study after study. It makes it hard for the researchers involved to listen to another idea about people with a strong BIS. After all, they've dedicated their careers to studying this trait. Grrr.

"I've Got It: Arousal Is Not Always Anxiety!"
"Hey, We Knew That."

In 2000, however, Gray and a colleague, Neil McNaughton, unwittingly came to the rescue. They revised his theory in an important direction that gives HSPs space to be seen as sensitive without necessarily being fearful. That revision is what I want to talk about. And it was certainly about time.

Actually, Gray sensed he would need this revision even in 1982 because he was troubled about one point: If the BIS checks everything to see if it's dangerous, not just threatening things, then it can't be a system only designed to detect danger--it's got to be sensitive to everything, and that would include good things too. After all, when you first see something, you don't know yet if it's good or bad. And Gray knew all along that those with a strong BIS were in fact more sensitive to all stimuli.

Why didn't he call it high sensitivity? Well, I can imagine many reasons, but clearly it never entered his head at the time.

If you can understand it, the revision is spelled out in the title of the McNaughton and Gray paper: "Anxiolytic action on the behavioral inhibition system implies multiple types of arousal contribute to anxiety" (in the Journal of Affective Disorders, p. 161-176; the earlier paper is cited there as well). I will try to translate. In their opening summary they say, "Our recent experiments show that there are multiple systems controlling theta activity..." Theta activity is active processing--thinking, comparing, problem solving, planning, or worrying. What HSPs do a lot of. "And that anxiolytics [anti-anxiety medications] act on several, but not all of these systems." That is, with at least some anti-anxiety medications, especially the newer ones (Xanex and Buspar), people are less anxious, yet their thinking--in our case the depth of our thinking or our sensitivity--is not at all impaired.

They go on to say that "This pattern of results implies that there are many different types of arousal, only some of which appear to contribute to the generation of anxiety in normal subjects and to the etiology [that is, source or cause] of pathological anxiety."

See? Gray himself says that those with a very active BIS are not necessarily anxious, in the moment or chronically. Specifically, Gray describes three types of arousal associated with the BIS, following the observation of arousal in animals.

Three Types of Arousal

One type of arousal leads to simple interest. Attention. A very thorough, interested processing of the situation. In animals, it occurs when no predator is present, but the animal does want to check to be sure, as well as wanting to check for anything new, interesting, or promising. Something possibly even very good. So in this case the BIS can be as optimistic as the BAS. It just hasn't given the go ahead yet.

Another kind of theta activity or aroused, intense processing leads to anxiety. This is a mixture of wanting to stay and see more, perhaps even move forward into the situation, and another part that says this looks a little like danger. In animals, this is the behavior when a predator just might possibly be present. The usual result is that there's a long tense pause with some sense of fear. Inhibited behavior.

The third type of theta activity is thought related to straightforward fear. Red alert! Predator. All arousal and processing is now focused on survival strategies.

Again, the first type of arousal I have described is arousal without fear. It's just attention--the sort of arousal that leads to thorough processing. So, again, Gray is announcing, in effect, that being an HSP or having a strong BIS does not automatically equate with having more anxiety. It may seem like a small point, but almost every description of this trait has been in terms of it being a greater fearfulness, even though it made no sense that evolution would quickly eliminate individuals who are constantly fearful. They'd miss out on too many opportunities to feed and mate, besides it being too hard on the body to be constantly on high alert. (The latest example of this error is found in an otherwise very revealing article in the New York Times Magazine, Sunday January 22, on the new field of "Animal Personality." In study after study described in the article, from fruit flies and fish to dogs and chimps, animals that hold back are referred to as shy and fearful, not sensitive and observant.)

So we still need a better name for the trait, and the next theory comes much closer.

A Theory about Why, With a "Protective" Childhood, HSPs Function Better Than Non-HSPs

I have often cited the research done by W. Thomas Boyce (along with nine others), a professor in the School of Public Health at the University of California, Berkeley, which found that "reactive" children who are not growing up in a stressful home or school environment were actually physically healthier than non-reactive children in the same environment. In a bad environment, however, "reactive" children are less healthy than non-reactive children. In 2005 Boyce and Bruce Ellis (University of Arizona) have published a two-part paper in the journal Development and Psychopathology providing more evidence of the same type. Equally important, they renamed the trait, calling it "biological sensitivity to context" or BSC, and they mount a vigorous argument that "stress reactivity" or fearfulness is definitely the wrong name for it. "Sensitivity" is better. So they really are very close. I will quibble in a moment, but first let's celebrate.

What Boyce and Ellis mean by BSC is that there is a gene that leads to what they call "biological sensitivity to context" because it has a feature found in some genes called "conditional adaptability." Specifically, it allows during childhood, while the brain is still developing, for three different adaptations to three different environments. The gene does this by "up regulating" or "down regulating" the systems that make us reactive to stress (what Gray called the BIS, plus other parts throughout the body as well).

In a high stress environment, the BSC gene in children will be activated, causing them to be very sensitive to stress. This will help them survive in the dangerous situation in which they were born because they will be very quick to react to danger with "fight" or "flight."

In a very low stress environment, created by being raised by very dedicated, responsive parents, the BSC gene will also be up regulated, so that these children will also be very alert to their environment. But this time it will be so that they can take maximal advantage of this "high parental investment." Up regulation allows these children to "absorb more fully the beneficial, protective features of supportive, predictable environments" (p. 289).

What About the Children Living with Moderate Stress?

Those living in moderately stressful environments will down regulate the BSC gene. The reasoning is that these children are better off not being too reactive to stress, since there will be some stress in their lives, but not so much that the advantages of being on alert and anxious would outweigh the disadvantages.

In relation to McNaughton and Gray's work, above, you could say (although they do not quite) that Boyce and Ellis theorize and find that the up regulated BSC gene involves all three kinds of activities of the BIS--greater reactivity means greater attention, especially important in good environments, as well as more anxiety and fear in dangerous environments.

So here's my quibble. It seems that their theory would require there being no HSPs who have had only moderately stressful environments, since in them the BSC gene would be down regulated. And I don't think that is the case. We all know HSPs with childhoods that were "so so." Further, the theory equates BSC with malleability, but this is a rather "empty" name for the trait, as if all it does is adapt to the outer world. Malleability does not do justice to the richness of the inner life of all HSPs--the intuition, appreciation of the arts, conscientiousness, empathy, spirituality, creativity, more vivid dreams, and all the rest. I think HSPs develop these to quite a high degree characteristics in all environments, not just protective ones.

Still, these are two interesting breakthroughs in theory. I hope to report soon on more data about HSPs, from research based on our own familiar view, from the inside, of what sensitivity is all about.

February 2006 Articles:
A Letter from Elaine
Reflections on Research: Ignored No Longer: New Interest in Us, New Theories about Us
Parenting Sensitive Children: Growing Up Gifted Is Not Easy
Sensitive Emotion: HSPs and the Problem of Bearing an Unbearable Emotion

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