They’re enigmas to most of the world. They “over-think,” “over-feel,” and have an almost eerie ability to read a roomful of strangers at a heart-level. They can go from “life of the party” to needing a three-day nap with no social interaction. And, when they come out of hiding, they go about saving the world with their empathetic do-gooding and creativity. Who are these alien earthlings? And what are the ways a Highly Sensitive Person’s brain is different from the brains of…well…the not-so-sensitive?

Put another way, why is an HSP’s brain considered the “most powerful social machine in the known universe”?

(If you aren’t sure if you are an HSP, take this quiz to find out.)

What is High Sensitivity?

High Sensitivity (HS) is a trait, present at birth, in about 15-20% of the population. It has no gender-bias, and it’s not a disorder or diagnosis.

People with the HS trait are ultra-responsive to what’s going on in their environment. Highly Sensitive People (HSPs)  notice darn near everything, and they process it all deeply. They’re extremely perceptive.

In general, American culture views sensitivity as a weakness. HSPs are used to hearing, “You’re too sensitive” and “You need to lighten up.” In other cultures (e.g. Japan), however, sensitivity is considered a strength.

The scientific name for High Sensitivity is Sensory Processing Sensitivity (SPS).

Scientists have discovered SPS in over 100 species, including fish, birds, dogs, monkeys, and horses.

The fact that the trait exists in so many species suggests it has some kind of evolutionary advantage as a survival strategy.

Why else would 10-15% of dachshunds or guppies be Highly Sensitive?

Because they’re more responsive to their environment, animals (and people) with SPS are more aware of opportunities, such as food and mating options. 

They’re also more aware of threats, such as predators, and are more prepared to respond.

In other words, HS provides a survival strategy of being observant before acting. The wait-before-acting approach guarantees that a species continues to evolve. (This sensitive survival strategy is only beneficial if found in a minority.)

Let’s briefly review what a Highly Sensitive Person is before discussing the Highly Sensitive Person’s brain.

“DOES” is a helpful way to remember the 4 pillars of High Sensitivity.

  1. Depth of processing: HSPs are deep thinkers.
  2. Over-arousal : HSPs are prone to anxiety and overwhelm due to deep processing.
  3. Empathy: HSPs have a huge capacity for empathy; they feel emotion deeply.
  4. Sensory specific sensitivity: HSPs tend to be sensitive to smells, bright lights, loud sounds, tastes, and tactility.

All features in the “DOES” framework are due to differences in the Highly Sensitive Person’s brain.

How does the Highly Sensitive Person’s brain work differently than the brain of someone who is not HS?

Understanding a Highly Sensitive Person’s brain brings clarity to the why and how of an HSP’s experience.

1. While at rest, a Highly Sensitive Person’s brain works harder than the brain of someone who is not an HSP.

Why? Because of stronger activation in parts of the brain (the cingulate and premotor area/PMA) responsible for visual and attention processing.

HSPs process everything deeply, even when not reacting to something specific in the here-and-now. An HSP could be processing something from three hours ago or something  suddenly remembered from last month.

So, in plain terms, the brain of a Highly Sensitive Person never really shuts off – even at rest.

 2. At least three sets of genes and their variants distinguish a Highly Sensitive Person’s brain from the brain of a non-HSP.

The three genes are responsible for serotonin, dopamine, and norepinephrine.

  • Serotonin Transporter:

Serotonin is a neurotransmitter and hormone that helps neurons communicate with one another. It’s central to mood and emotion because it’s primary function is to stabilize mood.

Serotonin transporter is a chemical that transports serotonin out of the brain.

HSPs have a variant of the serotonin transporter encoding gene, known as 5-HTTLPR. The 5-HTTLPR gene variant decreases serotonin in the brain and increases sensitivity to surroundings.

The HS brain may have less mood-stabilizing serotonin than the non-HS brain, but it has an enhanced ability to learn from experience.

The presence of this gene variant enhances the effects of both good and adverse childhood experiences.

This may explain why childhood experiences – both positive and adverse – so dramatically impact wellbeing for  HSPs.

For better or worse, HSPs’ childhood experiences affect them more than do the childhood experiences of non-HSP.


This neurotransmitter is known as the reward chemical.

If you have a sensitive nervous system, you don’t need much to feel “rewarded” by external stimuli. Chaotic, noisy, loud environments exhaust rather than excite you.

Carry that reality over to an environment like a loud football stadium, and you and your non-HS friends are likely to have very different experiences. Their “dopamine hit” will probably register as unsettling for you.

The explanation for this difference lies in the fact that the relevant dopamine gene variants all have to do with dopamine receptors. As an HSP, you simply don’t need the same amount of “reward” from external stimuli.

The same dopamine variant also explains why HSPs feel more rewarded by positive social or emotional cues.


Norepinephrine helps the body with the stress response. It’s also central to “emotional vividness,” or a person’s perception of emotional aspects in the world.

A variant of the norepinephrine gene, common in HSPs, boosts emotional vividness. If you have it, you experience emotional aspects of the world intensely.

You may also have more going on in parts of the brain that create internal emotional responses to experiences.

HSPs naturally respond more strongly to emotions than do non-HSPs. In addition, they notice emotional nuances when others don’t necessarily pick up on anything.

This ability to perceive emotional nuances – to “feeel” what others are feeling but not necessarily overtly expressing – is the foundation of empathy.

If you’re Highly Sensitive, this norepinephrine gene variant may be at least partly responsible.

3. HSPs have more active mirror neurons, which explains their gigantic capacity for empathy.

Mirror neurons are brain cells that help us understand what someone else is feeling. They’re involved in recognizing sadness and relating to it.

Because of such active mirror neurons, HSPs absorb emotions from people around them. Often they’re not even aware they’re doing so.

4. HSPs’ emotions are extra vivid due to a part of the brain called the ventromedial prefrontal cortex (vmPFC).

The vmPFC is involved in emotion regulation, especially the vividness of emotions.

The emotional vividness is not of a social nature (unlike mirror neurons). The vmPFC is more about how vividly HSPs feel emotions inside in response to what’s happening outside, in the environment. 

So HSPs often do have stronger feelings than other people because of the workings of their vmPFC. HSPs’ brains are so finely tuned that they can pick up on subtle emotional cues and react to them.

5. fMRI studies of the brain suggest the cortex and insula are more strongly activated among HSPs than non HSPs.

The insula is located deep in the brain. It has a lot of jobs, including interoceptive awareness.

Interoceptive awareness is about knowing what’s happening in your own body, such as hunger, thirst, and needing to pee. Emotions and moment-to-moment awareness are also part of the insula’s job.

By combining the most nuanced internal awareness with emotional context, the insula gives emotional meaning (e.g. pain, pleasure) to physiological states.

6. Another area of greater activation for HSPs is in the middle temporal gyrus (MTG).

This part of the brain has to do with emotional meaning-making. It’s involved in awareness of and response to stimuli. Examples of stimuli include things like loud sounds, strong smells, bright lights, and other people’s moods.

The Highly Sensitive Person’s brain is a gift.

It deeply processes information, makes interesting connections, and cares about people.

Science shows us that HS is associated with certain genes and patterns of brain activation. It’s not just hypothetical or theoretical.

The High Sensitivity trait is real.

An extra-special HSP gift is the one your brain gives to YOU. It is the gift of protection.

Your brain is able to recognize and understand what is going on around you. You see things coming before they happen.

So, the next time someone comments on your sensitivity, let the smile of knowing (and gratitude) spread across your face.

Offer to go into detail about the science and inborn nature of High Sensitivity. You know, the cingulate, premotor area, serotonin, dopamine, norepinephrine, mirror neurons, ventromedial PFC, insula.

The superpower stuff you came into the world with.

See how your critic processes that!

Dr Elayne Daniels is a psychologist, international coach, and consultant in MA whose absolute passion is helping other Highly Sensitive People thrive. Contact her here.