Elaine N. Aron's Blog, page 2

Revisiting Vulnerable Narcissism and HSPs

In August 2022, I wrote a blog strongly questioning an article saying that high sensitivity (HS) can “overlap” with vulnerable narcissism (as opposed to the grandiose form).  Scott Barry Kaufman wrote a good blog on this too. Vulnerable narcissists are a relatively new idea, a category of narcissist born from the observation that they are highly focused on themselves—”am I good enough” and all that, to the point that they fail to consider what others are feelings. It can make anyone seem selfish or callous if their only thought seems to be, “What do you think? How am I doing?” Or, “Wow, congratulations—I wish I were that good.”

While there was some truth to the possibility that HSPs could also sometimes have these tendencies, the article implied something of a basic similarity between HS and narcissism in its use of the term “overlap” (referring to the fact that on a questionnaire, both HSPs and vulnerable narcissists will be somewhat likely to say yes to a few particular items, such as “I worry that I am not good enough.”).  This idea of an overlap ignores where there is no overlap–for example the strong empathy characteristic of HSPs and the lack of it in all varieties of narcissism.

Recently Scientific American covered the research on narcissism, both the grandiose and new vulnerable type (not mentioning HSPs of course). It was then that I realized there is a far better way to separate normal HS from vulnerable narcissism, based on the fundamental nature of narcissism that none of the researchers are seeing.

I believe narcissism is basically a problem of being obsessed by ranking. You will immediately get this, I think, if you understand ranking and linking from reading any of the places I have discussed it (for example, my book The Undervalued Self or my first Psychology Today blog But for those of you who do not see the connection, I will review the idea in light of narcissism.

Reviewing Ranking and Linking

Like other social animals, we constantly rank ourselves among others—comparing, competing, or after enough of that, just “knowing our place,” so that it rarely comes up. If you bring a treat to a group of horses, dogs, monkeys, or giraffes—any social animal living in a group–you will immediately know who the alpha is. He or she gets the treat and the others back off. It can be more subtle among humans, but often not much. In any group, we know everyone else’s rank in the social hierarchy, while trying to maintain or maybe raise our own. (What you rank others on depends on you and the particular group—it could be kindness, popularity, income, social skills, etc., not just tennis playing or Scrabble scores.)

Ranking is automatic and very useful. Imagine every day having to figure out at work who’s best at each job, including President. When ranking is settled and clear it saves energy, outright fighting, and the resulting wounds, of all types. Of course, it can be fun to compete and even more fun to win. The trouble with ranking is being challenged, and at some point we all experience defeat. That’s why we mostly like rankings to be stable.

Just as often, however, we are engaging in our other social instinct, linking. Social animals have friends, too. If you watch them in groups, there are certain specific ones they hang around. In humans, linking means liking or loving certain others, so that we want to be near them, get to know them, and meet their needs if we can. Obviously linking brings far more comfort and pleasure, and although I have no data on it, in general HSPs especially seem to prefer to link.

What Goes Wrong?

The reason I wrote The Undervalued Self was that I realized as a therapist that although patients came in wanting closeness, connection, and to feel loved, they tended to think in terms of ranking, especially that they are not as good as others, do not deserve respect or caring, and then in our relationship, cannot believe I really like them. They feel I am too superior to them to actually care for them.

When someone suffers from low self-esteem and depression, it is almost always due to having an insecure adult attachment style, learned in infancy. As children the love they received was inconsistent and contingent on certain behaviors. So that as children they always had to be on guard to keep their caregivers loving them. These adults can become vulnerable narcissists.

There is another insecure attachment style, being avoidantly insecure. These people learned as children to act like they do not care how the caregiver (usually neglectful or abusive) treated them. As adults they are the same way, determined not to care.  It’s easy to do if you feel superior to everyone. These people can become grandiose narcissists, switching to the vulnerable type when they are unable to maintain enough admirers.

You can easily see how either type of insecure child can learn to see the world in terms of ranking. Anxious insecurity keeps the child one-down. The caregiver has all the power to bestow love or walk away. The avoidant type tries to be one-up by acting indifferent, by seeming to possess all the power to stay or leave. But beneath the bravado there is an even deeper insecurity.

All of this insecurity occurs in a family when there is not enough linking going on. Some ranking is always going on in families. Caregivers always have more power—hopefully it is what I call power in the service of love, wanting the other to grow into equality, and the child senses the love behind the boundaries or even criticism. Indeed, no boundaries and can make a child anxious. But some families are nothing but ranking. And constant praise for achievements is of course another way of saying, “your rank in the world is all that matters to me.” It is certainly the source of grandiose narcissism in many people.

What about those with a secure adult attachment style? A secure attachment style means you are confident that most people will like you and you will like most people—that linking prevails in this world.

A preoccupation with ranking is not always from childhood. Blows to one’s ego in adulthood, again involving ranking, can also cause low self-esteem, as when someone chooses to end a relationship with you, or your business fails. But these are not usually as persistent as the effect of always experiencing ranking at home, without love and linking. It’s persistent ranking at home and at school, with little or no linking, that leads to an obsession with ranking in adulthood—that is, to narcissism.

Can Narcissism Be Innate?

The research on narcissism does find a small genetic component. Psychopathy, which is generally innate, is just intense ranking—that is, an extreme case of narcissism. For instance, rhesus monkeys, similar genetically to humans, have an innate trait of heightened ranking behavior and aggressiveness. Males with the trait are often ostracized and generally do not live long. The trait endures because females inheriting the trait are dominant in the female group and so their offspring have all the resources they need, and some will have inherited the trait and pass it on.

What about vulnerable narcissism being innate? I doubt there is a gene pattern directly causing it, but it might develop in someone who inherits any characteristic that made them feel that others saw them as inferior (for example, a learning disability or being very short), so they grow up feeling low in rank for that reason. But environment is also always a factor (in that case, parents and teachers might keep the child from feeling inferior). But generally, look into the family life of a narcissist, whether grandiose or vulnerable, and you will see how they became obsessed with rank.

I think you can understand how all of this applies to HSPs. We are not innately narcissistic, and I think very few of us become vulnerable narcissists in the sense of losing all track of others’ needs and being callous or calculating. If we are insecurely attached, we are likely to just try to please others. True, we could miss the cues of what others need if we assume they are like us–skilled linking requires knowing the other person, not just projecting onto them that they will like us if we try hard enough.

A Word About Grandiose Narcissism

About grandiose narcissism, I believe this sometimes is not due to childhood environment but created by acquiring a very high rank and influence over others as an adult. Having too much power. There is considerable research on how people, given power, will start to use it for their own advantage. Having power, they get used to having their own way. To most people in power, it feels good.  That is, they are changed by having power and become more narcissistic. (For a review of some of this work, see Keltner, D., Gruenfeld, D. H., & Anderson, C. (2003). Power, approach, and inhibition. Psychological Review, 110(2), 265.) This applies to almost anyone, for example research participants randomly assigned a role of power over others in an experiment. When taken to an extreme, we see political figures and spiritual leaders, to take two prime examples, sometimes horribly misusing their power financially or sexually. Very often they never would have thought of it until the door was left wide open and they just walked through it. But that is another subject.

Mostly I just wanted to take this opportunity to remind you to try looking at the world, including narcissism, through this lens of ranking and linking. Even though most of the world’s problems are caused by ranking on a massive scale, very often some genuine linking, just a hug and some sympathy, works wonders. Love helps.

Highly Sensitive High Sensation Seekers—Giving Equal Love to Both Parts

This blog is about high sensitivity and high sensation seeking because we published a recent article on the subject. by Bianca Acevedo, Art Aron and me, Tracy Cooper, and Robert Marhenke: “Sensory processing sensitivity and its relation to sensation seeking,” in the 2023 issue of Current Research in Behavioral Sciences, 4, 100100. Read full article here. 

If you are highly sensitive and not a

, well, what I say about having children also applies to having the high sensation seeking trait: “It’s wonderful if you do and it’s wonderful if you don’t—it’s just a different kind of wonderful.” Indeed, being moderately high on sensation seeking as well as being highly sensitive sometimes feels like I do have a bored child traveling with me, constantly asking “When do we get there? What are we going to do there? What are we doing after that?” I love her, but oh what a pain she can be. So, love yourself either way, okay?

Also, there are all degrees of sensation seeking—very high, high, moderate, moderately low, low… It may be that you do have this trait, perhaps just a little bit more than not, just a little above average, and you do not know it because your highly sensitive part has kept it under control. So do take the test on this website here.  And of course, read on also if you want a glimpse into those who do have the combo even though you do not. 

I am not sure of the year when I realized that highly sensitive people (HSPs) could also have the trait of high sensation seeking (HSS), but I know I rewrote the standard measure of high sensation seeking in order to it include in my book The Highly Sensitive Person in Love, which was published back in 2000. I did that because I wanted to write about what happens when one person in a relationship has a trait that the other does not, and I knew from personal experience and meeting many HSPs who were also HSS that it was a particularly important trait to include.  Given how much the traits are in conflict within a person, I saw that there also is going to be conflict when one person has this trait and the other does not.

The reason I had to revise the standard measure, published by Marvin Zuckerman, was that it had questions that involved high risk taking—doing something that could possibly seriously hurt you or doing something illegal, and I knew HSPs would not answer yes to those questions. So I had to write a version that was HSP-friendly. But after the book came out, we never published the new, HSP friendly version in an academic journal, so no other scientists were aware of it. We finally remedied that this year, with this article.

Of course, many people think that HSPs could not be high sensation seekers because that would get them overstimulated.  “Aren’t those traits opposites?” But the opposite of high sensitivity is actually impulsivity—acting without thinking first. HSPs like to think everything over before they act. That is the essence of the trait. So if they want a new experience, they first have to learn all about it. High sensation seeking is not about risk taking, but more about being easily bored and liking variations in one’s routine, such as taking a trip or trying new foods. Check out Tracy Cooper’s book Thrill, the High Sensation Seeking Highly Sensitive Person.

The HSS/HSP study was done online, which is quite standard these days, with 217 participants filling out measures of sensitivity, impulsivity, risk-taking, and two measures of sensation seeking. One of the two was the standard HSS measure, with questions about being easily bored and liking to try new things, but also questions that involve being impulsive (“When I’m feeling good I tend to get into situations that could cause me problems)” or taking risks (“I would take a risk even if it might get me hurt”). The other HSS measure was the one I wrote for my book, specifically for HSPs. 

The results? On the standard measure of HSS, HSPs tended to score a bit lower than others. That was because of the impulsivity and risk taking questions. On the measure specifically designed for them, they did not score lower than others.  That is, there was no association between HS and HSS. That means that when measured properly, the two traits are independent. Or, about fifty percent of HSPs are high sensation seekers and about 50% are not, or put yet another way, there is a 50-50 chance that you or any other HSPs is a high sensation seeker. Of course there are degrees of HSS, so we are talking about being on one side of the midpoint or the other. 

Another interesting result was that when HSPs were experiencing negative feelings, they tended to be a bit more impulsive than those without the trait, showing “negative urgency.” That is a good reason to stay within your comfort zone, with plenty of downtime and boundaries.  You don’t want to get a bit crazy and do something impulsive just because you are overstimulated.

The Problems, and They Do Not Go Away

Having both traits can cause real inner conflict.  I have written about this before here, as has Tracy in his book. Imagine there are two versions of you living inside—the HSP and the HSS. Frequently the conflict results in one part feeling regret–the HSS part can get you into situations that your HSP part really does not like. For example, your HSS part gets you to go to a party.  You do and you have a terrible time. Regret. But suppose the HSP part keeps you from going. Now you worry that you may have missed out on a great time. Regret also. 

How many parties have I been to and felt so glad I came? Well, not many. But some. And of course, both parts can end up unhappy—the party is overstimulating so the HSP is mad, but it’s also boring, so the HSS part is mad! The problem is that you cannot know if something will suit you until you try it. So you have to use your sensitivity to consider all the evidence and the clues about how it may work out, carefully weighing the odds about whether you should go ahead. Maybe you finally decide by simply considering whose turn it is to choose!  Have you stayed home too much lately or gone out too much?  Avoided risks or taken too many?  

Be sure to give credit to the HSS part when you strike it rich doing something new and exciting. Perhaps the best experience of my life was a thirteen-day oar-boat trip through the Grand Canyon, Glen Canyon Dam to Lake Mead.  The HSS insisted on it.  Of course, everyone else in the group was going mostly for the Class 5 (most dangerous) rapids. They were clearly very high on sensation seeking and not HSPs. I was going to see the beauty, and I will never forget it. Nor will I forget the total of 15 minutes of Class 5 rapids spread over all those days. That part was simply terrifying for the HSP. Not to mention that we slept on the sand by the river and sometimes were bit by fire ants. The weather was too hot, the water too cold, and it was all so hard. I stepped on a rock and cut my foot, and the first aid given, to be sure I did not get an infection, had me literally shrieking, embarrassed as I was. But no part of me, no part, including the HSP, regrets that adventure.   

Being Fair to Your HSS Part

Frankly, it seems now that we have endless advice for keeping the HSP in us happy—downtime, boundaries, the right sort of work and lifestyle. But I have only recently accepted that I must keep the HSS part of me happy too. I had always seen it as frivolous, demanding, wanting to travel when that is not good for the environment, and overall just a waste of time. Not getting work done. Or not belonging in a peaceful, deep, reflective person. But I find that when I ignore the HSS part, it just causes trouble. I fee bored, flat. Really flat.

The problem has been so easily solved, for me. You might do it another way. But I make sure I have new things in my life. I make sure that I have at least one interesting thing coming up during the week, and that I have one interesting book to read, and, yes, one TV show I like (there really are not many of those). Doing that, I am so much happier. There also needs to be a bigger thing coming up later in the year, like a trip for a few days or weeks. The HSS part keeps it all in mind. Too much going on or coming up, I am not happy. But nothing is coming up? I am just as unhappy.

I finally realize that I will be trying to balance my two sides for the rest of my life. In fact, getting older has created new challenges. It’s more difficult to find something new for the HSS part. Over the years I have seen most of the movies and read most of the books that have appealed to me, which were never many, and I do not like watching a movie or reading a book twice. I have traveled to every place of interest within a day’s drive and to most of the places throughout the world that my highly sensitive part considers safe. I like to hike, but we have done all the nearby hikes. We like to kayak on the nearby Russian River, but we have done it so many times that I know every sandbar.

Another problem with getting older, one that the HSS part refuses to acknowledge, is that it gets less safe or comfortable to do some things. I had to give up horseback riding after a fall that resulted in a concussion because getting another concussion at my age often leads to dementia. The HSP in me said, “NO thanks. I value my brain more than riding horses.” I ache more than I used to after long hikes. Long downhill hikes I no longer do at all—something goes wrong in one knee. Air travel long distances only works for me if we can save up enough to go business class. What a baby!  

One of my grandsons, an HSP/HSS, is crazy about sailing. I always loved sailing too–to me it is a lot like riding horses–but I never had a chance to sail until my grandson fell in love with it. After he had taken enough lessons, my son got him the twenty-foot “Flicka” sailboat that he had been begging for. Everyone else in the extended family gets seasick except me and him. So now we two sail together. But both of us want to sail to new places, which means longer trips. My back protests the long sitting.  Exploring new places also means sailing even farther and anchoring out overnight. That requires sleeping on the boat with all of its challenges for an older person. The routines that keep me healthy and the HSP happy are quite disrupted by all of this. At my grandson’s age he has no problem, of course, and my HSS part wants to be just like him. He plans to sail around the world someday. The HSS in me is screaming like an angry little girl, “I want to go with him!” But it cannot be.

Suggestions

For me, the main solution is staying creative—making or writing something no one else has is I think part of being high in HSS.  So I am writing a book on something entirely different from high sensitivity, not because I lost interest in HSPs, but I feel like I have said all I can say. I do keep up with the research, because it is new.

I also use my creativity to find new activities for the HSS. I keep searching for what I still have not done, seen, felt, etcetera that would neither be scary nor boring. That narrow area. Sometimes I simply do the same thing in a different way. Hike the same trail by moonlight or in the rain. Or bring someone along, allowing me to see everything freshly through their eyes. I keep in touch with new offerings of the things I know I love. Plays, concerts, the ballet, and even the museum—they all have new seasons. 

As for aging, eliminating some things, I make the HSS accept it.  For me the only solution is graceful acceptance. I do not bemoan it to others or let the HSS part blame the HSP part. Aging is part of life. Enough said.

Finally, I think of these two parts as a team, each with their strengths. Really, aren’t they better together? All that adventure and curiosity from the HSS part, and all of D.O.E.S. from the HSP, especially the Depth of processing, the Empathy and strong Emotion, and Sensitivity to the Subtle.) If I think about being one without the other, that would not be me, would it? All this is me. We have to be the temperament we were born with and learn to love it all. About this we do not have to make a choice.  

Mental Health Awareness Month – Supporting HSPs & Highly Sensitive Youths – Guest Blog by Alane Freund, MS, MA

Guest Blog by Alane Freund, MS, MA

May is mental health awareness month. For 2023, the Mental Health Awareness month campaign “is focused on how surroundings impact mental health, and we are calling for individuals to look around, look within.” In 1949, Mental Health America (MHA) designated May as Mental Health Month to raise awareness and “to spread the word that mental health is something everyone should care about.” This is an important theme for HSPs and Highly Sensitive Youth. Why? We are more impacted by our surroundings than anyone without high sensitivity.

“Look around and look within” and you will surely see the people, places, and things in your surroundings that are impacting your mental health. These impacts can be both healthy and problematic. Remember, we are better at healing. When we improve our surroundings… We get BETTER! Mental Health Awareness month is a time for us all to remember that we have the power to heal. We can heal and be healthy because we react to the good stuff even more than we react to the bad stuff. You can create the good in your surroundings, in your life, and in your heart and mind.

I often hear from HSPs who say, “I understand that sensitivity is a gift, but I just don’t feel it because I find myself having to isolate or be aloof in order to survive.” The truth is: We can’t underestimate how important our childhood experience is to how we feel and function today. HSPs who had a childhood that was more difficult or not supportive enough need a lot of support to experience the gift(s) of being highly sensitive. I’m one of those HSPs–A lot of twelve step work and a lot of therapy and a lot of exercise and a lot of meditation and a lot of the other kinds of self-care…And it’s still hard sometimes! The struggle is real! And so is our phenomenal ability to heal.

Guest Blog by Alane Freund, MS, MA.  Alane is an International Consultant on High Sensitivity (ICHS) and family therapist who helps highly sensitive adults and youth focus on solutions through therapy, consultation, and speaking. Ms. Freund has developed and implemented programs for highly sensitive people, youth, families, and the clinicians who serve them. She holds Masters’ degrees in both clinical psychology and school counseling and is the parent of a highly sensitive young adult. Ms. Freund’s Talk at Google, Understanding the Highly Sensitive Person, is a widely recognized resource.  In addition to her YouTube channel, Alane Freund LMFT, she hosts the twice monthly Are You Highly Sensitive LIVE membership workshops. Her innovative programs include HSPs & Horses™ and the online Sensitivity Circle topics: Parenting Sensitivity, Sensitive Youth, Wise Women & Wonder, HSProfessionals, HSPs in Relationships, and HSMen. Alane offers team building, educational workshops, and retreats at Heart and Mind Equine in California and across the globe, She can be reached for consultation or speaking through her website, alanefreund.com

Mental Health Awareness Month – Supporting HSPs & Highly Sensitive Youths

May is mental health awareness month. For 2023, the Mental Health Awareness month campaign “is focused on how surroundings impact mental health, and we are calling for individuals to look around, look within.” In 1949, Mental Health America (MHA) designated May as Mental Health Month to raise awareness and “to spread the word that mental health is something everyone should care about.” This is an important theme for HSPs and Highly Sensitive Youth. Why? We are more impacted by our surroundings than anyone without high sensitivity.

“Look around and look within” and you will surely see the people, places, and things in your surroundings that are impacting your mental health. These impacts can be both healthy and problematic. Remember, we are better at healing. When we improve our surroundings… We get BETTER! Mental Health Awareness month is a time for us all to remember that we have the power to heal. We can heal and be healthy because we react to the good stuff even more than we react to the bad stuff. You can create the good in your surroundings, in your life, and in your heart and mind.

I often hear from HSPs who say, “I understand that sensitivity is a gift, but I just don’t feel it because I find myself having to isolate or be aloof in order to survive.” The truth is: We can’t underestimate how important our childhood experience is to how we feel and function today. HSPs who had a childhood that was more difficult or not supportive enough need a lot of support to experience the gift(s) of being highly sensitive. I’m one of those HSPs–A lot of twelve step work and a lot of therapy and a lot of exercise and a lot of meditation and a lot of the other kinds of self-care…And it’s still hard sometimes! The struggle is real! And so is our phenomenal ability to heal.

Guest Blog by Alane Freund, MS, MA.  Alane is an International Consultant on High Sensitivity (ICHS) and family therapist who helps highly sensitive adults and youth focus on solutions through therapy, consultation, and speaking. Ms. Freund has developed and implemented programs for highly sensitive people, youth, families, and the clinicians who serve them. She holds Masters’ degrees in both clinical psychology and school counseling and is the parent of a highly sensitive young adult. Ms. Freund’s Talk at Google, Understanding the Highly Sensitive Person, is a widely recognized resource.  In addition to her YouTube channel, Alane Freund LMFT, she hosts the twice monthly Are You Highly Sensitive LIVE membership workshops. Her innovative programs include HSPs & Horses™ and the online Sensitivity Circle topics: Parenting Sensitivity, Sensitive Youth, Wise Women & Wonder, HSProfessionals, HSPs in Relationships, and HSMen. Alane offers team building, educational workshops, and retreats at Heart and Mind Equine in California and across the globe, She can be reached for consultation or speaking through her website, alanefreund.com

Last of the 2022 Research

I promised to finish up the research in 2022 and after that only present the very best studies and comment on those further.  But here are the last good studies of 2022.  Remember, you can always just read the title and “bottom line.”  I know some of you will be fascinated, some bored.  Above all, be happy with all the research being done, putting us on the scientific map!

Sensory processing sensitivity and axonal microarchitecture: identifying brain structural characteristics for behavior. 

David, S., Brown, L. L., Heemskerk, A. M., Aron, E., Leemans, A., & Aron, A. (2022). Sensory processing sensitivity and axonal microarchitecture: identifying brain structural characteristics for behavior. Brain Structure and Function, 1-17.

This study another example, using totally different methods, of how much the brains of those high in SPS differ from those low in the trait.  Previous research on the brain and SPS has mostly used functional magnetic resonance imagining (fMRI), but this study used a new method, diffusion tensor imaging (DTI, measuring diffusion of water in the axon) to look for “axonal microstructural differences,” which are differences in the arrangement of white matter of the brain.

We had available 408 participants from the Human Connectome Project. Also known as the Young-Adult Human Connectome Project, the National Institute of Health created this free data bank to obtain a map of the functioning of the normal brain by doing DTIs on 1200 young, healthy subjects, plus having them take many psychological tests, and making those results available for research.  Of course, the participants in the Human Connectome Project did not take the HSP Scale, so we had to create a “proxy” SPS questionnaire using individual questions from other questionnaires they had taken that seemed by their contents to measure SPS.  (This first attempt at a “proxy” HSP measure was given along with the HSP Scale to a large number of people, and only the items correlating best to the HSP Scale were used in the final proxy measure.)

The results?  The differences in HSPs and those without the trait in microstructure of their white matter in specific cortical regions were consistent with what had been found in fMRI studies, although there were a few new ones related to attention and cognitive flexibility, empathy, emotion, and first levels of sensory processing, as in the primary auditory cortex.

Bottom Line: Once again, SPS is shown to be a real trait, in that those with it have brains that look and perform differently than the brains of those who do not have it.  Can’t be simpler.

2. Emotional Contagion and Mirror System Activity in the Highly Sensitive Person.

Ishikami, Y., & Tanaka, H. (2022). Emotional Contagion and Mirror System Activity in the Highly Sensitive Person. In International Symposium on Affective Science and Engineering ISASE2022 (pp. 1-4). Japan Society of Kansei Engineering.

Understanding that HSPs are thought to have more empathy but that questionnaires about one’s empathy can be inaccurate, the authors evaluated empathy using an electroencephalograph (EEG) to measure mirror system activity (indicating a particular aspect of empathy)  and another experiment to look for emotional contagion (another kind of empathy).

In the first study, participants were shown a video of someone raising a cup.   While watching the cup being raised, participants with an HSP Scale score of 100 or higher showed “event-related desynchronization of 50% or higher,” indicating greater mirror system activity.

In the second part of the study, on emotional contagion, when people looked at an image of a happy face, those with higher HSP Scale scores showed lower alpha wave band power values. Since alpha waves are associated with relaxed states of non-arousal, it was inferred that the happy face created happy feelings, which increased HSPs’ arousal and reduced their alpha rhythms. Interestingly, neutral or sad faces did not. Thus, it was found in these two studies that the higher the HSPs score, the greater the level of mirror system activity and of emotional response to seeing someone looking happy, all of which indicates greater empathy without using questionnaires to ask about it.

Bottom Line: Once again a brain measure finds what questionnaires have also shown:  In this case that we have more empathy and a greater positive response to positive emotions in others.

3. Variability in the Relationship Between Parenting and Executive Functions in Early Childhood: The Role of Environmental Sensitivity.

Oeri, N. S., Kunz, N. T., & Pluess, M. (2022). Variability in the Relationship Between Parenting and Executive Functions in Early Childhood: The Role of Environmental Sensitivity.

Executive functioning refers to the ability to plan, focus attention, remember instruction, and multitask when necessary.  Very poor executive functioning is the same as Attention Deficit Disorder.  In this study, executive functioning was higher for HSCs whose parents reported more involved parenting, while it was substantially lower for HSCs whose parents reported using corporal punishment. No such effects emerged for less sensitive children.  This is a straightforward case of differential susceptibility.

Bottom Line:  This is just what we would expect:  A child who is over aroused all the time, fearing punishment, will not be able to develop executive functioning as well as a child who feels supported and securely attached to parents.

4. The relation between sensory processing sensitivity and telomere length in adolescents.

Jentsch, A., Hoferichter, F., Raufelder, D., Hageman, G., & Maas, L. (2022). The relation between sensory processing sensitivity and telomere length in adolescents. Brain and Behavior, 12(9), e2751.

Telomeres are repeated DNA sequences located at the ends of chromosomes, and their length reduces naturally over time, so telomere length (TL) is considered a biomarker of cellular aging.  But stress and certain personality traits are associated with shorter TL as well.  Its meaning is really not well studied in young people, but in a study of 82 healthy adolescents, aged 13–16, from secondary schools in Germany, students with higher scores on the HSP Scale were likely to have shorter telomeres.  TL could be associated with simply having the trait, but if stress is the cause, well, we know HS adolescence in public schools are certainly under stress.

Bottom Line: This may mean we need to improve the lives of HS high school students, which we should do anyway.

5. Investigating the relationship between sensory processing sensitivity and relationship satisfaction: Mediating roles of negative affectivity and conflict resolution style.

Zorlular, M., & Uzer, T. (2022). Investigating the relationship between sensory processing sensitivity and relationship satisfaction: Mediating roles of negative affectivity and conflict resolution style. Current Psychology, 1-10.

This study looked at 200 Turkish couples age 18-25 in romantic relationships (not married or living together) for at least 24 months.  The authors emphasized that HSPs tended to have less satisfying relationships if they displayed a tendency to have negative emotions or poor conflict resolution skills and those high in SPS tend to have more negative emotions.  But they did not point out that if you statistically control for negative emotions—that is, hold it to be the same in everyone—there is no correlation between SPS and relationship dissatisfaction or satisfaction.  (They also looked at the effect of one’s childhood and found no relationship with SPS and satisfaction, but it was not a good measure of childhood.)

Bottom Line: We can imagine many reasons why HSPs in a relationship might be negative and also dissatisfied with it. But this study is clear that just being an HSP does not interfere with being happy in a relationship.

6. Environmental Sensitivity in Adults: Psychometric Properties of the Japanese Version of the Highly Sensitive Person Scale 10-Item Version.

Iimura, S., Yano, K., & Ishii, Y. (2022). Environmental Sensitivity in Adults: Psychometric Properties of the Japanese Version of the Highly Sensitive Person Scale 10-Item Version. Journal of Personality Assessment, 1-13.

The important part of this study was not revealed in its title:  In order to show that their 10-item scale was valid, in the last of a series of four studies reported in the article they showed a short positive video to the study participants (85 Tokyo college students) and gave them a measure of how happy or sad they felt.  Only those high on their HSP Scale had more positive feelings after watching the video, an example the authors said of vantage sensitivity.

Bottom Line: In spite of all the talk about our negative emotions and tendency to neuroticism, on average we enjoy positive experiences more than others do!

Research from 2022 on High Sensitivity

It is nice to keep showing you the research. There is so much more of it now and it is so varied. If you want you can skim this easily, by just reading the titles of the studies and the “Bottom Line.” But enjoy the overall effect–the sense of the growing interest by scholars in this subject.

1. The Temperament Trait of Environmental Sensitivity is Associated with Connectedness to Nature and Affinity to Animals.

Annalisa, S., Francesca, L., Rachel, K., Liam, M., & Michael, P. (2022). The temperament trait of environmental sensitivity is associated with connectedness to nature and affinity to animals. Heliyon, 8(7), e09861.

In two studies, the higher the HSP Scale score, the greater the expressed connectedness to nature. In the first study, attachment to pets was also studied, and there was no difference on that between HSPs and those without the trait. I guess everyone loves their pets! The second study looked at “animal affinity” in terms of stewardship and protection of animals, and HSPs were higher on that. Again, both studies found the greater connectedness to nature.

Bottom Line: This is no surprise. HSPs do love to be outside and to be with animals. But now we have
data to demonstrate it.

2. Genetic Sensitivity Predicts Long-Term Psychological Benefits of a Relationship Education Program for Married Couples

Pluess, M., Rhoades, G., Keers, R., Knopp, K., Belsky, J., Markman, H., & Stanley, S. (2022). Genetic sensitivity predicts long-term psychological benefits of a relationship education program for married couples. Journal of Consulting and Clinical Psychology.

It is well known that relationship-education programs can promote relationship quality and prevent divorce among married couples. Given how well HSPs respond to interventions (anti-bullying, resilience, development, etc.), the researchers wanted to see if HSPs would gain more than others from a high quality relationship program. In two studies, with 182 and 242 participants, they identified HSPs by the latest genetic methods, using genome-wide association. The higher the level of sensitivity as indicated by the genetic markers using this method, the stronger the effects of the intervention on almost all measures of relationship quality across the follow-up period.

Bottom Line: Once again we see that HSPs benefit more than others by high-quality programs and interventions (and probably books, online courses, therapy, etc.).

3. Sensory processing sensitivity and culturally modified resilience education: Differential susceptibility in Japanese adolescents

Kibe, C., Suzuki, M., Hirano, M., & Boniwell, I. (2020). Sensory processing sensitivity and culturally modified resilience education: Differential susceptibility in Japanese adolescents. PloS one, 15(9), e0239002.

Speaking of benefiting more from interventions, this study replicated with Japanese adolescents the study published in 2015 by Pluess and Boniwell showing that a resilience education program had far more impact on HS teenage girls than on girls without the trait. In this study, 407 Tokyo high school students (both boys and girls) were tested for resilience, self-esteem, self-efficacy, and depression before, right after, and three months after the resilience intervention. All students benefited, but the
HSPs, who scored significantly lower on well-being at the start, gained the most. In particular their depression dropped and self-esteem rose.

Bottom Line: Once again we see differential susceptibility and responsiveness to interventions. While differential susceptibility can mean being more affected by a negative environment, in this case simply being an HS adolescent, the good news is that with HSPs the negative can be more easily mitigated or avoided.

4. Environmental sensitivity and cardiac vagal tone as moderators of the relationship between family support and well-being in low SES children: An exploratory study.

Moscardino, U., Scrimin, S., Lionetti, F., & Pluess, M. (2021). Environmental sensitivity and cardiac vagal tone as moderators of the relationship between family support and well-being in low SES children: An exploratory study. Journal of Social and Personal Relationships, 38(9), 2772-2791.

Seven-year-old children from socioeconomically disadvantaged families were individually interviewed to determine how much support they felt they received within their family as well as to assess their physical and emotional well-being. Their sensitivity was measured by a series of tasks developed by the researchers. And the interesting variable in this study was cardiac vagal tone, a measure of how well the vagus nerve and heart are working together. The better the “tone,” the better a person handles stress. The children were divided into high, medium, and low sensitivity groups and measured for their cardiac vagal tone which, interestingly, did not differ among the groups. But HSCs with higher cardiac vagal tone and with low or only moderate support at home evidenced greater well-being than children in the same low-moderate-support family environment who were not highly sensitive.

Bottom Line: It is interesting that cardiac vagal tone is not associated with being highly sensitive, but it certainly helps HSPs to have it. Perhaps it can be developed.

5. Is Sensory Processing Sensitivity associated with psychoactive substance use?

Mary-Krause, M., Bustamante, J. J. H., Collard, L., & Melchior, M. (2022). Is Sensory Processing Sensitivity associated with psychoactive substance use? Emerging Trends in Drugs, Addictions, and Health, 100038.

Using data from 862 French adults, 25-44 years of age, researchers looked at the relationship between SPS, using the 12-item HSP Scale, and the degree of use of psychoactive substances, including tobacco, alcohol, cannabis, and illicit drugs. High SPS was observed among 14% of their subjects. There was no association between SPS and psychotropic use.

Bottom Line: If you are asked (I often am) whether HSPs are more prone to drug use, you can say research suggests they are not.

The Big Bottom Line: These are such an interesting mix of studies looking for how HSPs might differ, from connection to nature to drug use to gaining more from interventions. These broad effects are because an innate trait like this is going to affect everything you do. So just keep enjoying the validation that this trait of yours is real and has some lovely effects.

Research: High Sensitivity Wrongly Identified with Narcissism, Plus Studies on Parenting Applied to Managing and Caregiving

This blog on research needs a long introduction before coming to the studies themselves.  After receiving questions about the research article “Do highly sensitive persons display hypersensitive narcissism?” that came out in February, I knew it was going to be an issue for HSPs.  Hence the first half of this blog.

As a heads up, the second half of this blog is a discussion of three research articles on HSPs as parents, published in 2019-2020.  But my “bottom line” for each is for non-parents too, because each study’s findings relate to any job in which an HSP is caring for or managing others, especially on a daily basis.   I was planning to discuss these studies anyway, but doing them now demonstrates that I do not simply discuss research that is all positive about HSPs until I was forced to discuss this article on narcissism. I report to you any studies that seem to be sound research.

Actually, if it were not for the subject matter of narcissism, I would not have bothered even to write about this article for you due to its flaws in terms of its interpretation of results and missing a key variable.  I do not mean to be hard on the authors.  But, in particular, I do not report articles that discuss HSPs having more of some problem than others do (e.g., burn out, low self-esteem, feeling stressed, having various disorders), as these researchers did, without taking into account differential susceptibility—that HSPs vary widely in their physical, mental, and social health depending on their childhood experiences. More on that in a moment. Many researchers make that mistake, but it was unfortunate in this case.

About the Lead Author and “Public Discourse”

The lead author of this study is a postdoctoral researcher (a normal step between earning one’s doctorate and gaining a university position) in Graz, Austria.  He and another of the authors have published several articles on narcissism, so I think we can call them experts in that area.  The trouble is, researchers tend to see their specialty everywhere, right?  So while the authors understand narcissism and see it everywhere, they know less about high sensitivity, also called sensory processing sensitivity (SPS).  But having done considerable reading of the “public discourse” by HSPs on the internet, they have naturally seen narcissism there sometimes.

I realize this public discourse about HSPs can give the impression of narcissism (that we feel we are different and special), but I think the authors failed to cut some slack for those groups (including HSPs) who have felt mistreated as a minority.  I think some members of ethnic and racial groups also try to find ways to express that they are really quite amazing (e.g., the popularity of “Black Excellence” as a term), and it seems like an important stage in healing sometimes.  One also has to realize that those speaking up on social media are not representative of all HSPs, but often are those who have felt particularly mistreated, perhaps echoing a personal history of trauma and abuse.

A few good media articles dealing with this research study and the “public discourse” have come out, making my job easier.  One is a well-balanced discussion at Psychology Today by psychologist, Scott Barry Kauffman, who is featured in the upcoming film Sensitive Men Rising. (A less helpful Psychology Today article [let’s not put in the link—it was not a good article] is by Preston Ni, simply describing the way that narcissists can sometimes be hyper or “highly sensitive” to criticism.)  Meredith Kavanaugh [Alie insert the link for her that I sent] also rushed to our defense arguing that we are basically the opposite of narcissists.  She is not a researcher so misses some of the arguments being made, but her thoughts are comforting and accurate in other ways.  I’m sure there will be more articles and blogs.

An Interview of with the Lead Author

The study I am discussing is now being more widely read because of a recent article, with an interview of the lead author, on Psychpost, “Study Suggests that Highly Sensitive Persons Exhibit Characteristics of Vulnerable Narcissism.”  (Psychpost publishes readable stories about research in psychology and neuroscience.) He said in the interview that “Our study showed that high sensitivity and hypersensitive narcissism are not the same thing, but they do have significant overlaps.”  I will discuss the use of the term “overlap” shortly.  He said his article was not an attempt to “pathologize” high sensitivity, but rather “to study all aspects of high sensitivity and narcissism — including the favorable and unfavorable aspects,” and “we wish to emphasize that we try to regard neither of the constructs as ‘pathological’ or ‘normal’ in nature.”

Hm. That feels a bit insensitive!  Two of the study’s authors actually did a study of how the public views the term and found “Narcissism is often portrayed one-sidedly and overly negative, rendering a picture of narcissistic individuals as “toxic people” or “evil characters.” That is quite an admission when you then associate the term with a group of people who already feel misunderstood.  

Whatever his intentions, he is admitting that the public hears “narcissism” as pathology, and therefore anything “overlapping” with it is also pathologized.  That is, his interview is his apology.  “Didn’t mean it.”  Okay.  So now we must deal with this.

A New Front in the Continuing Struggle to Educate Mental Health Professionals

More serious perhaps than this fresh “public discourse” is that the journal that published the article is highly respected and widely read by clinical psychologists, meaning that some therapists will return to their view of high sensitivity as a “personality problem” at best, not an innate trait. In the abstract the authors state that the “Nomological networks were similar [high sensitivity and vulnerable narcissism] and pointed to a neurotic‐introverted personality profile with reduced personality functioning.” And for therapists, “this points to the importance of being attentive to narcissistic self‐regulatory strategies in individuals presenting as highly sensitive.”

Oh geez.  But again, all is okay.  There are ups and downs, and as HSPs make themselves more visible on the internet in a wide range of ways (some of which I would not choose), there are bound to be reactions.

If you read the full research article, you will see more troubling statements.  For example, that HSPs “do share self-regulatory mechanisms which likely counteract personal growth in the long run.”  And again, “One of the main suggestions for clinicians working with patients who consider themselves highly sensitive, or for readers who see aspects of high sensitivity in themselves, could be to critically evaluate aspects of a high sensitivity mindset with respect to the extent to which they really benefit the individual.”  What “self-regulatory mechanisms” are threatening the HSP’s personal growth?  What “mindset”?  I fear they are referring to the fact (not imagined) that HSPs need to develop a lifestyle that takes advantage of their creativity and deep thinking without exposing them to high levels of stimulation.  Perhaps such a lifestyle/mindset appears to inhibit personal growth if personal growth means learning not to be overstimulated when doing all the same things as those without the trait. 

I think we are seeing the usual human tendency to assume everyone is like us, and when someone is different from ourselves, we tend to doubt the reality of that.  “They are just making it up.” Or, “since this does not look normal to me, this is really a disorder.” It is true that some HSPs over-regulate or are too “in,” avoiding stimulation.  But this is usually due to trauma in the past that needs to be worked on, not the trait itself.

What is especially unfortunate is the authors quoting a researcher who studies truly pathological narcissism and is talking about “hypersensitivity” in that disorder, not at all about SPS, when she says, “overwhelming hypersensitivity and reactivity (visceral, psychosomatic, or affective) [in pathological narcissists] tend to supersede or overpower actual awareness of and ability to verbalize internal experiences.” The authors of this paper, not the author of that quote, conclude from this that HSPs could in a similar way develop “self‐sustaining dynamics of overwhelming experiences and a sense of being fundamentally different from others.”  There it is again, the subtle implied question:  “How could any normal person feel fundamentally different than ‘normal’ me?”

The message to therapists seems to be that instead of appreciating that HSPs are unusually aware of internal experiences, they should be watching for HSPs being unusually NOT aware of internal experiences or able to verbalize them, so that they are feeling overwhelmed for no reason.  Therefore whatever they are verbalizing is not accurate, and they could need considerable treatment to rectify this.  Well, I will not say more.  It will raise my blood pressure!  Let’s look at the research itself and give you some take-aways to use in conversations should “HSPs-as-narcissists” ever come up, especially with a therapist.

         1. Do highly sensitive persons display hypersensitive narcissism?

Jauk, E., Knödler, M., Frenzel, J., & Kanske, P. (2022). Do highly sensitive persons display hypersensitive narcissism? Similarities and differences in the nomological networks of sensory processing sensitivity and vulnerable narcissism. Journal of Clinical Psychology, 1-27.

Let’s begin with the obvious fact that some HSPs ARE narcissists.  This is not because the traits overlap or are somehow similar at a deep level, but because narcissism is a personality trait (not innate like a temperament trait) that is thought to arise due to a troubled childhood.  At its extreme it is a personality disorder, a real problem for the person and those around them, although the article under discussion is supposed to be more about “normal” narcissism.

The point is, differential susceptibility immediately enters in, which this research article does not mention.  That is, HSPs with good childhoods will be more free of mental, physical, or social problems than those without the trait with similar good childhoods.  There is no “overlap” in the sense of similarity with any disorder.  But those with poor childhoods could be even more liable to develop something like the kind of narcissism described in this article (or develop chronic depression, anxiety, shyness, etc.) than those without the trait.

We need to be clear, however, that psychologists talk about two kinds of narcissism (and neither kind are considered disorders until they reach certain levels).  The first is the grandiose, outgoing, sometimes even charming type, but full of a sense of entitlement and willingness to use others. This is what everyone thinks of as narcissism. No one (including the authors of this study) is claiming that HSPs are that type. But there is a more vulnerable “covert” kind of narcissist, involving shyness, defensiveness, and low self-esteem.  

These vulnerable narcissists are “hypersensitive” to social stimuli.  For example, in a social setting they feel stressed because they think others are watching them.  They are not particularly bothered by physical stimuli.  The authors admit the difference, that HSPs are bothered mostly by physical stimuli, but see both as likely to lead to irritability, a sense of differentness, and a sense of entitlement to an environment without such stimuli. (In fact, HSPs did not show much of that sense of entitlement, although it is seen in some HSPs’ “public discourse” quite a bit, that the world is not designed for HSPs and it ought to be.)

Again, no one is arguing that SPS “overlaps” with the grandiose kind.  But by focusing on the contents of the self-report measures of SPS and “vulnerable” narcissism, one does see an association of a certain type, which the article then interprets as a “nomological” overlap, in that the items on one measure had some similarities to items on the other (although statistically there was actually little overlap).  But an association does not mean that being an HSP overlaps with being a narcissist.  An association in research refers to a statistical association, or a “correlation.”

Pardon me for the statistics lesson about to come, but everyone should understand a little bit about correlation.  It is expressed as a decimal and can run from a negative one through zero to a positive one.  A and B are somewhat positively correlated (.32 .56, etc.) if, for example, on a questionnaire people who answer yes to A are also somewhat more likely than others to also answer yes to B.  If people who say yes to A are somewhat more likely to say NO to B, there is a negative correlation (-.45, -.60, etc.).  If how A is answered by people appears to have almost nothing to do with how B is answered, the correlation is essentially zero.  (By the way, correlation does not mean causation—that A causes B or B causes A.  Watch for that in advertising when it is implied that using A causes less of B.  That using A is associated with less B does not mean that A is what is reducing B.  Experiments are required to demonstrate that.)

In the narcissism study the HSP Scale correlated around .50 with measures of vulnerable narcissism, but this correlation dropped to .30 when items measuring “neuroticism” or “negative affect” were statistically taken out–“partialled out” or “controlled for.”  Because of differential susceptibility, in most of our research we also control for neuroticism whenever we use the HSP Scale. This is mainly because the HSP Scale has too many negatively worded items (we are currently revising it to add items on depth of processing, empathy, and perceiving subtle positive stimuli). We know that some people who are not HSPs but had a bad childhood and therefore are high on negative affect will also score high on the HSP Scale and be counted as HSPs if we do not control for negative affect.

Please understand that a correlation does not mean there is an “overlap” in everyone.  It does not mean that everyone who answered A a lot or a little also answered B a lot or at least a little bit.  The results in this article mean that a small to moderate percentage of  people, not all, who appeared to be HSPs also appeared to have characteristics of vulnerable narcissism. Very likely those are also the HSPs who had poor childhoods.

To see it more clearly, think of what we have learned about SPS and high sensation seeking (HSS).  Yes, some HSPs also have the trait of HSS. But that does not mean there is any “overlap” between SPS and HSS.  It just means that some HSPs score high on both measures. Both.  But statistically the measures of the two traits are not even correlated.  Zero correlation.  There are just as many HSPs who are low on SS (when it is properly measured, without items related to high risk-taking and high impulsivity).

Bottom Line: First, when HSPs are seen as similar to narcissists, they are referring to a type of narcissism that has nothing to do with being grandiose, entitled, or using others.  It refers to “vulnerable narcissism,” which means just that–feeling self-conscious and vulnerable.  This is not at all what narcissism means to most people in the general public.

Second, do not forget differential susceptibility, a central fact about all HSPs:  Raised in a reasonably good environment they do better than others, but in a poor one they do worse.  Hence this misnamed narcissism, “vulnerable narcissism,” which is caused by a troubled childhood, will certainly show up in some HSPs.  But it does not mean that high sensitivity and even vulnerable narcissism “overlap” in the sense of being similar traits.  There are plenty of HSPs who are not even slightly narcissistic in any of the senses used by psychologists.

Third, in designing their study and interpreting their results, the article relies considerably on impressions from “public discourse,” but does not consider how many HSPs may completely ignore all of that, including the self-help books that portray sensitivity as a superpower or that treat it as a special burden, all of which understandably sounded to the authors very narcissistic (and commercial).  I doubt that most HSPs think much about their trait as either a superpower or a burden once they have integrated it into their thinking, so that other people rarely hear them talk about it.

What follows are studies on parenting dating from 2019 and 2020, but my “bottom lines” will relate the research to all forms of professional care giving (in that I include parenting and teaching) and management.

       2. Sensory Processing Sensitivity and the Subjective Experience of Parenting: An Exploratory Study

Aron, Elaine N., Arthur Aron, Natalie Nardone, and Shelly Zhou. “Sensory Processing Sensitivity and the Subjective Experience of Parenting: An Exploratory Study.” Family Relations (2019).

This was an online survey of more than 1,200 English-speaking parents, both sensitive and those without this trait. The basic results were that highly sensitive (HS) parents tended to find parenting more difficult, but they were also more attuned to their children and more creative.

There were two survey samples. The first was mostly mothers, so we could not look at mothers and fathers separately (and mothers in both samples had similar results). In the second, there were 802 mothers and 65 fathers, a little better for analyzing fathers. On average, the HS fathers found parenting a little more difficult than the fathers who were not HS. But this was a small effect and not statistically significant, and that they were smaller than for mothers was probably due to the mothers usually being more directly involved with caregiving. Compared to fathers without the trait, the HS fathers did report greater attunement to their children, just as HS mothers had, and this was strong enough to be statistically significant in spite of the small number of fathers and even smaller number of HS fathers within the sample.

Bottom Line: HS parents and probably teachers, caregivers of all sorts, and managers—anyone dealing all day with people of whatever age—probably feel more attuned to those under their direction than those who do not have the trait.  They are probably more creative in solving all sorts of situations, given that HSPs are in general more creative than others.  At the same time, like parents (I have often heard this from HS teachers and managers), they report finding managing others on a daily basis more difficult than others find it.  So, I hammer home the same message always—your wonderful attunement requires that you stay rested!  Or, it may devolve into something you are less proud of, as found in the next two studies.

      3. Sensory sensitivity and its relationship with adult attachment and parenting styles.

Branjerdporn, Grace, Pamela Meredith, Jenny Strong, and Mandy Green. “Sensory sensitivity and its relationship with adult attachment and parenting styles.” PloS one 14, no. 1 (2019): e0209555.

This study of parents with children aged 4-12 found that, on the average, HS parents were not performing as parents quite as well as those without the trait. This was indicated by their self-reported parenting styles. You may have heard of these styles. There are three. At one extreme there is the authoritarian style, emphasizing obedience and strict limits (high standards, low communication). At the other extreme is the permissive style, few limits and mainly trying to please the child (high communication, low standards). In the middle, the ideal is authoritative, giving children structure and limits, but in a caring, listening way (high communication, high standards). HS parents tended to say they were using one or the other of the extremes, strict or permissive, more often than they described themselves as using the middle, ideal authoritative style.

Of course, parenting style varies all day long, but the authors of the article saw it the same way that I do. The extremes probably do not represent parenting philosophies associated with being an HSP, but that HS parents are reporting one of these two styles, and possibly using both at different times, because they are so often overwhelmed and are just admitting to how they usually handle their child’s demands during those times.

You can imagine how this goes.  Maybe the parent, desperate for rest, decides strict limits are the only answer right now.  The parent says, “This is quiet time.  I need to rest.  Go to your room and play there. Or rest.  But I don’t want to hear a sound out of you.”  Child starts to protest. Parent interrupts. “You know the consequences if you don’t do as I say, right now.  No story time tonight.   Now I’m counting to three. No, I don’t care if you want to play here ‘real quietly.’ I will come and get you when I’m done resting.”

The other scenario is that, again, the parent just has to have quiet time and will do anything to get it, so starts out with, “This is quiet time.  Please go to your room to play so I can rest.”  The child says, “But Mommy, I want to play here!” (starting to whine, then sob).  “No, when you play with those toys you are often too noisy.”  “No, I will be real quiet.”  “If you go, maybe we can play together later.”  “No!  I hate you!” (Screaming now.)  So, the parent caves in.  “Okay.  Yes, I know, you feel terrible.  Okay, play here then, but keep it quiet. I mean it.”

Bottom Line: With children or any other group you must manage daily, again, stay rested.  Watch for a tendency to be too lenient or too strict to save yourself stress.  Or, if or when you have a choice, maybe you do not want the stress that comes with constantly working with/for people!  HSPs can be very, very good at it.  But it takes its toll.  Watch out for when the quality of your work with others slips into “Just listen to me” or “Sure, do whatever…”

       4. How do highly sensitive persons parent their adolescent children? The role of sensory processing sensitivity in parenting practices.

Goldberg, A., & Scharf, M. (2020). How do highly sensitive persons parent their adolescent children? The role of sensory processing sensitivity in parenting practices. Journal of Social and Personal Relationships, 37(6), 1825-1842.

This study looked at parenting practices with adolescent children and parents’ attachment “style,” specifically insecure attachments–anxious or avoidant. One hundred twenty-one parent–adolescent dyads completed self-report questionnaires assessing parents’ sensitivity and attachment style and their parenting practices.  (Self-reports have a problem, of course, as HSPs as a group might be more honest or aware of their parenting or their attachment than non-HSPs, and thus come up “worse,” but we cannot assume that.)

The results showed that being highly sensitive while parenting a teenager was associated with inconsistency, psychological intrusiveness, and an “anxious” attachment style (not the avoidant attachment style). It seems that having an anxious attachment style might lead to HS parents being overly attached to their child, not wanting to lose them, which can be a real challenge when children are seeking autonomy in adolescence.  Hence both harsh parenting and intrusiveness might arise as ways for the anxious parent to try, unconsciously, to keep the growing child from developing independence.

The authors conclude that “Interventions focused on regulating high-SPS parents’ stress and on facilitating parents in practicing separating their own and their children’s emotions could promote their use of more positive parenting practices.”

Bottom Line:  People of all ages can act like teenagers sometimes!  One day or minute they want to be independent from you, maybe more than they are ready for, and the next they are being clingy, wanting comfort and guidance from you.  Especially if you are tired, these swings can trigger your own attachment style, how you felt as children about your caregiver.  In particular, if someone is pushing for independence or more distance or separation from you, and you have an anxious attachment style, that can trigger some behaviors in you that the other might see as intruding or obstructing.  But if you are aware of it and rested, you can control it.

More HSP Research

These are more interesting studies, from various dates.  I am still catching up.

1.Role of Childhood Adversities and Environmental Sensitivity in the Development of Post-traumatic Stress Disorder in War-Exposed Syrian Refugee Children and Adolescents.

Karam, E. G., Fayyad, J. A., Farhat, C., Pluess, M., Haddad, Y. C., Tabet, C. C., … & Kessler, R. C. (2019). Role of childhood adversities and environmental sensitivity in the development of post-traumatic stress disorder in war-exposed Syrian refugee children and adolescents. The British Journal of Psychiatry, 214(6), 354-360.

This is a fascinating study. The participants were over 500 Syrian refugee children (7-17) living and going to school in Lebanon. Michael Pluess and his co-authors assessed for high sensitivity, childhood adversity, and intensity of negative war events they had experienced, from being unable to leave the house because of gunfire and knowing of friends’ homes having been destroyed to being tortured or seeing a family member killed. The question was, how would prior childhood adversity (e.g., having had parents who hit or neglected them, who fought with each other or screamed at the child, or having had abusive siblings, etc.) change the effect of war stress on children with various levels of sensitivity?

Differential susceptibility (that HSPs do better in life if they had good childhoods but worse with bad ones) and common sense might predict that with better childhoods, sensitive children would handle war stress better than non-HSCs. But they did not. If a child was highly sensitive, the better the childhood, the more PTSD.

Once you digest this result, I am sure you can think of several reasons for it. Basically, more sheltered HSCs must have found wartime events more shocking. This makes sense, given the difficulty for HSCs making transitions and dealing with overstimulation. In contrast, those with prior childhood adversity at home were used to hell. War was more of the same.

One might also wonder if the HSCs with bad childhoods had developed what is called an avoidant attachment style, taking the self-protective attitude that “I don’t need anyone—I can do fine on my own.”  They detached early in their lives or were fully dissociated, so that maybe they did not fully feel new trauma.

Or perhaps dangers or injuries befalling family members might not have distressed them as much. It might have even oddly helped them—their abusive family members were distracted or might even be entirely gone from their lives. Meanwhile, the sensitive child with a happier family life would feel more dependent on their family members and fear more for their safety.

This study also reminds me of one of Israeli soldiers being studied for their likelihood of suffering PTSD. The researchers used the short serotonin allele (sometimes thought of as one genetic source of SPS) as a likely predictor of PTSD after exposure to battle. They found, however, that while soldiers with this allele were more distressed by training, in battle they were less distressed, or at least not as prone as others to PTSD. I have always imagined that during training they were very anxious about how they would survive and paid close attention to everything they could learn that would help them. Hence in actual battle they were a little calmer and more confident (and safer) than those who had not taken their training so seriously.

That could suggest that, similarly, maybe the HSCs with adverse childhoods had simply developed “street smarts” early and were not surprised or unprepared when things got even tougher in their lives. When bombs started falling, they had well-rehearsed ideas and skills about how to survive.

Bottom Line:  That’s science. The question was, do HSPs with good childhoods suffer less PTSD from war? We might have thought the answer was yes, they were protected, but it was no. That answer opens up a dozen new hypotheses to test.  Or just things to ponder with a more open mind–in this case, about what it means to be an HSC in this crazy world.

2. Predictors of Psychological Risk and Resilience Among Syrian Refugee Children

Meanwhile, hot off the press: Popham, C. M., McEwen, F. S., Karam, E., Fayyad, J., Karam, G., Saab, D., … & Pluess, M. (2022). Predictors of psychological risk and resilience among Syrian refugee children. Journal of Child Psychology and Psychiatry.

This study continued to look at Syrian children in refugee camps in Lebanon, this time 1,528, seeking to find out how children differed in their response to the trauma and ongoing difficulties in their lives. About 19% had only a few symptoms or problems, the rest did have significant difficulties. As we would expect, being highly sensitive was one variable that was associated with more symptoms. Note that this study was not looking at differences among the childhoods of highly sensitive children.

Bottom Line:  As you would expect, in general being highly sensitive (not considering prior history as in the study above) is one risk factor for suffering from being a refugee, although the study shows that very few children do well in this situation.

3. Sensory Processing Sensitivity and Entrepreneurial Intention: The strength of a Weak Trait.

Harms, R., Hatak, I., & Chang, M. (2019). Sensory processing sensitivity and entrepreneurial intention: The strength of a weak trait. Journal of Business Venturing Insights, 12, e00132.all

Harms, Hatak, and Chang have done research (using methods from business research) on those with the intention and sense of having the ability to start one’s own business (entrepreneurial intention).  Previous research has associated entrepreneurial intention with a “heroic,” extraverted, not-very-sensitive type. However, these researchers found HSPs have also been found to have a strong entrepreneurial intention, being skilled at recognizing opportunities (depth of processing, aware of subtle stimuli, creativity, etc.) and motivated to be self-employed, so that they can manage their own energy and resources.

Bottom Line: This seems a perfect description of why HSPs can do so well running their own business.

4. The Sensitive, Open Creator; Sensitive Individuals are More Creative

Bridges, D., & Schendan, H. E. (2019). The sensitive, open creator. Personality and Individual Differences, 142, 179-185.

Bridges, D., & Schendan, H. E. (2019). Sensitive individuals are more creative. Personality and Individual Differences, 142, 186-195.

The first of these two articles reported a study involving 288 participants and finding sensitivity associated with several highly regarded measures of creativity, finally providing evidence (we never say “proving”) that HSPs are more creative, on at least some measures, than those without our trait. The second article is an in-depth review of similar research and an explanation of why sensitivity is a key overlooked factor in creativity.

Bottom Line:  How nice to have this research to back up what we thought—HSPs are unusually creative.

5. Do Overwhelmed Expatriates Intend to Leave? The Effects of Sensory Processing Sensitivity, Stress, and Social Capital on Expatriates’ Turnover Intention.

Andresen, M., Goldmann, P., & Volodina, A. (2017). Do overwhelmed expatriates intend to leave? The effects of sensory processing sensitivity, stress, and social capital on expatriates’ turnover intention. European Management Review, 15(3), 315-328.

You may remember the lovely, charming, brilliant Maike Andresen from her appearance in the film Sensitive:  The Untold Story. I visited her in Germany and taught for a day her students in the department of Human Resource Management at the University of Bamburg, Germany (one of the most prestigious in Europe), where she is a full professor and chair of the department. Her specialty is global careers and expatriation, and in this study, she looked at how being an HSP affected the “turnover intentions” (either to resign or a company’s intention to “let them go”) of employees working abroad.

The researchers found that HSPs were more often sent overseas on important assignments, but were higher on turnover-intention measures, with stress being the reason. Since organizations sent more than average numbers of HSPs to these positions, they apparently thought HSPs were especially suited for these jobs in other cultures (with their empathy, conscientiousness, etc.). Hence the conclusion was that more preparation and support, to help them deal with the stress, would allow them to be retained in these roles.

Bottom Line: How often HSPs are promoted into more responsible positions because of all their good qualities, but they exhaust themselves and/or perform less well than expected because the position as it is designed is too stressful for them. Wonderfully, Maike is saying, don’t give up on them, but prepare and support them better.

HSP Research Update

These are more interesting studies, from various dates.  I am still catching up.

Role of Childhood Adversities and Environmental Sensitivity in the Development of Post-traumatic Stress Disorder in War-Exposed Syrian Refugee Children and Adolescents.

Karam, E. G., Fayyad, J. A., Farhat, C., Pluess, M., Haddad, Y. C., Tabet, C. C., … & Kessler, R. C. (2019). Role of childhood adversities and environmental sensitivity in the development of post-traumatic stress disorder in war-exposed Syrian refugee children and adolescents. The British Journal of Psychiatry, 214(6), 354-360.

This is a fascinating study. The participants were over 500 Syrian refugee children (7-17) living and going to school in Lebanon. Michael Pluess and his co-authors assessed for high sensitivity, childhood adversity, and intensity of negative war events they had experienced, from being unable to leave the house because of gunfire and knowing of friends’ homes having been destroyed to being tortured or seeing a family member killed. The question was, how would prior childhood adversity (e.g., having had parents who hit or neglected them, who fought with each other or screamed at the child, or having had abusive siblings, etc.) change the effect of war stress on children with various levels of sensitivity?

Differential susceptibility (that HSPs do better in life if they had good childhoods but worse with bad ones) and common sense might predict that with better childhoods, sensitive children would handle war stress better than non-HSCs. But they did not. If a child was highly sensitive, the better the childhood, the more PTSD.

Once you digest this result, I am sure you can think of several reasons for it. Basically, more sheltered HSCs must have found wartime events more shocking. This makes sense, given the difficulty for HSCs making transitions and dealing with overstimulation. In contrast, those with prior childhood adversity at home were used to hell. War was more of the same.

One might also wonder if the HSCs with bad childhoods had developed what is called an avoidant attachment style, taking the self-protective attitude that “I don’t need anyone—I can do fine on my own.”  They detached early in their lives or were fully dissociated, so that maybe they did not fully feel new trauma.

Or perhaps dangers or injuries befalling family members might not have distressed them as much. It might have even oddly helped them—their abusive family members were distracted or might even be entirely gone from their lives. Meanwhile, the sensitive child with a happier family life would feel more dependent on their family members and fear more for their safety.

This study also reminds me of one of Israeli soldiers being studied for their likelihood of suffering PTSD. The researchers used the short serotonin allele (sometimes thought of as one genetic source of SPS) as a likely predictor of PTSD after exposure to battle. They found, however, that while soldiers with this allele were more distressed by training, in battle they were less distressed, or at least not as prone as others to PTSD. I have always imagined that during training they were very anxious about how they would survive and paid close attention to everything they could learn that would help them. Hence in actual battle they were a little calmer and more confident (and safer) than those who had not taken their training so seriously.

That could suggest that, similarly, maybe the HSCs with adverse childhoods had simply developed “street smarts” early and were not surprised or unprepared when things got even tougher in their lives. When bombs started falling, they had well-rehearsed ideas and skills about how to survive.

Bottom Line:  That’s science. The question was, do HSPs with good childhoods suffer less PTSD from war? We might have thought the answer was yes, they were protected, but it was no. That answer opens up a dozen new hypotheses to test.  Or just things to ponder with a more open mind–in this case, about what it means to be an HSC in this crazy world.

Meanwhile, hot off the press:

Predictors of Psychological Risk and Resilience Among Syrian Refugee Children.

Popham, C. M., McEwen, F. S., Karam, E., Fayyad, J., Karam, G., Saab, D., … & Pluess, M. (2022). Predictors of psychological risk and resilience among Syrian refugee children. Journal of Child Psychology and Psychiatry.

This study continued to look at Syrian children in refugee camps in Lebanon, this time 1,528, seeking to find out how children differed in their response to the trauma and ongoing difficulties in their lives. About 19% had only a few symptoms or problems, the rest did have significant difficulties. As we would expect, being highly sensitive was one variable that was associated with more symptoms. Note that this study was not looking at differences among the childhoods of highly sensitive children.

Bottom Line:

Sensory Processing Sensitivity and Entrepreneurial Intention: The strength of a Weak Trait.

Harms, R., Hatak, I., & Chang, M. (2019). Sensory processing sensitivity and entrepreneurial intention: The strength of a weak trait. Journal of Business Venturing Insights, 12, e00132.all

Harms, Hatak, and Chang have done research (using methods from business research) on those with the intention and sense of having the ability to start one’s own business (entrepreneurial intention).  Previous research has associated entrepreneurial intention with a “heroic,” extraverted, not-very-sensitive type. However, these researchers found HSPs have also been found to have a strong entrepreneurial intention, being skilled at recognizing opportunities (depth of processing, aware of subtle stimuli, creativity, etc.) and motivated to be self-employed, so that they can manage their own energy and resources.

Bottom Line: This seems a perfect description of why HSPs can do so well running their own business.

The Sensitive, Open Creator. 

Bridges, D., & Schendan, H. E. (2019). The sensitive, open creator. Personality and Individual Differences, 142, 179-185.

Bridges, D., & Schendan, H. E. (2019). Sensitive individuals are more creative. Personality and Individual Differences, 142, 186-195.

 

The first of these two articles reported a study involving 288 participants and finding sensitivity associated with several highly regarded measures of creativity, finally providing evidence (we never say “proved”) that HSPs are more creative, on at least some measures, than those without our trait. The second articles is an in-depth review of similar research and an explanation of why sensitivity is a key overlooked factor in creativity.

Bottom Line:  How nice to have this research to back up what we thought—HSPs are unusually creative.

Do Overwhelmed Expatriates Intend to Leave? The Effects of Sensory Processing Sensitivity, Stress, and Social Capital on Expatriates’ Turnover Intention.

Andresen, M., Goldmann, P., & Volodina, A. (2017). Do overwhelmed expatriates intend to leave? The effects of sensory processing sensitivity, stress, and social capital on expatriates’ turnover intention. European Management Review, 15(3), 315-328.

You may remember the lovely, charming, brilliant Maike Andresen from her appearance in the film Sensitive:  The Untold Story. I visited her in Germany and taught for a day her students in the department of Human Resource Management at the University of Bamburg, Germany (one of the most prestigious in Europe), where she is a full professor and chair of the department. Her specialty is global careers and expatriation, and in this study, she looked at how being an HSP affected the “turnover intentions” (either to resign or a company’s intention to “let them go”) of employees working abroad.

The researchers found that HSPs were more often sent overseas on important assignments, but were higher on turnover-intention measures, with stress being the reason. Since organizations sent more than average numbers of HSPs to these positions, they apparently thought HSPs were especially suited for these jobs in other cultures (with their empathy, conscientiousness, etc.). Hence the conclusion was that more preparation and support, to help them deal with the stress, would allow them to be retained in these roles.

Bottom Line: How often HSPs are promoted into more responsible positions because of all their good qualities, but they exhaust themselves and/or perform less well than expected because the position as it is designed is too stressful for them. Wonderfully, Maike is saying, don’t give up on them, but prepare and support them better.

More Research, from 2018 and 2019

I am continuing to close the gap between my 2017 report on research of HSPs/SPS (sensory processing sensitivity) and what is being published in 2022. In my last blog, I reported on the recent research and what had come out in 2021. Of course, I am already behind, with the new studies in 2022.  But here you will learn about what was published in 2018 and some of what was published in 2019. (I do not want to make these too long.)

In my next blog, I will describe other studies from 2019 and start on those that appeared in 2020. In the blog after that, 2022. If all these dates confuse you, the bottom line is you will eventually have everything. If you are interested in the research and missed the last blog, be sure to read it here. It also had comments on the research in general.

2018 Research

The Personality Trait of Environmental Sensitivity Predicts Children’s Positive Response to School-Based Antibullying Intervention Citation:

Nocentini, A., Menesini, E., & Pluess, M. (2018). The personality trait of environmental sensitivity predicts children’s positive response to school-based antibullying intervention. Clinical Psychological Science, 6(6), 848-859.

Antibullying interventions in schools work a little, but not a lot.  Would it be different if you considered differences in the students?  In a study of over two thousand students, grades four through six, researchers gave the HSP Scale designed for children and found that highly sensitive boys with high scores benefited much more from an intervention to reduce bullying than less sensitive boys.  That is, according to self-report questionnaires, highly sensitive boys after the program were victimized less and less depressed or anxious.  The highly sensitive girls also received more benefit than girls who were not highly sensitive, but the effect was not as great on girls as on boys. Clearly highly sensitive children, especially boys, are more likely to be victimized, so that is one explanation. All the students in the anti-bullying program were compared to a control group who were not in the program, so it was a well-done study.

Bottom Line:  If you were bullied as a child, don’t you wish this intervention had been done at your school?  If you have anything to do with schools, ask for it to be done!  It is not uncommon so there should be no problem. Look on the internet for tips.

Dandelions, Tulips and Orchids: Evidence for the Existence of Low-Sensitive, Medium-Sensitive and High-Sensitive Individuals

Citation:  Lionetti, F., Aron, A., Aron, E. N., Burns, G. L., Jagiellowicz, J., & Pluess, M. (2018 ), Dandelions, tulips and orchids: evidence for the existence of low-sensitive, medium-sensitive and high-sensitive individuals. Translational Psychiatry, 8(1), 24. doi: 10.1038/s41398-017-0090-6

This important study found that HSPs are closer to 30% of the population rather than 20% as we have been saying for years.  So far this seems to result in more and more studies.  That’s fine.  It’s how science progresses and we will all have to change what we say—30% are HSPs. Or as I still prefer, 20% to 30%.

This study also found that people fall into three distinct groups on the HSP Scale. Some of the authors (not myself and Art) decided to name the groups Orchids (30%), Tulips (40%), and Dandelions (30%).  I am not so fond of any flower terms for describing the presence or the absence of the trait, given how boys may feel about it.  But Orchids and Tulips were the terms coined by Tom Boyce, so that persuaded us to let it pass.  Having found this middle group, everyone thought the name Tulips seemed to fit.

Bottom Line:  I know 30% will take some getting used to, and I would not worry too much about changing it for now if you have said it or put it in writing.

The functional highly sensitive brain: a review of the brain circuits underlying sensory processing sensitivity and seemingly related disorders

Citation: Acevedo, B., Aron, E., Pospos, S., & Jessen, D. (2018). The functional highly sensitive brain: a review of the brain circuits underlying sensory processing sensitivity and seemingly related disorders. Philosophical Transactions of the Royal Society B: Biological Sciences, 373 (1744), 20170161.

In this study we (mostly Bianca Acevedo) compared studies of the brains of HSPs to studies of those with Autism Spectrum Disorder, Schizophrenia, and Post-Traumatic Stress Disorder (PTSD) doing similar tasks.  That is, subjects with these disorders were not in a study with HSPs, doing the same tasks, but studies of all four were compared, so that is a bit of a problem.  Nevertheless, it was easy to conclude that HSPs’ brains worked differently (although an HSP could still have any of these disorders—that is, one could be an HSP and also have PTSD.  Note that in the last blog the study on “performance in an emotional antisaccade paradigm” found HSPs were faster on the task, but those diagnosed with schizophrenia, ADHD, or autism had been found in other studies were found to be slower on this task.

Bottom Line:  Should it come up in a conversation:  Sometimes people suggest that HSPs are simply people with high-functioning autism, but studies continue to suggest otherwise.

2019 Research

Observer-Rated Environmental Sensitivity Moderates Children’s Response to Parenting Quality in Early Childhood

Citation: Lionetti, F., Aron, E. N., Aron, A., Klein, D. N., & Pluess, M. (2019). Observer-rated environmental sensitivity moderates children’s response to parenting quality in early childhood. Developmental Psychology, 55(11), 2389.

After years of hard work, there is finally a measure of HS in children too young to read. It was created by watching videos of children going through a particular set of activities while being observed by people trained in the method. So, it will not be easy to use unless children are observed in this set of activities.

Developing the measure was possible because we had videos that were part of a study going on over many years of the same children.  This kind of “longitudinal” study is a great research method. The videos of the children when they were about three had already been rated for “temperament” (positive and negative, fearful, inhibited) to see how temperament at that age would affect mental health when these children grew up.  So, the videos only needed to be re-rated for high sensitivity, which we decided would be rated as present in a child when we saw a mixture of holding back to watch closely at the start of an activity, but not seeming fearful, and then coming forward after a while in a curious, positive way, and being highly cooperative with experimenters.

The second major contribution from this study is regarding differential susceptibility. The HSCs, identified at three, were more affected at age six by how they had been parented compared to non-HSCs. If they were raised by parents who were “too permissive,” as rated when the children were three, they were more likely to have “internalizing problems” (depression, anxiety) when they were six. On the other hand, if raised by “authoritative parents” (considered the best parenting style), sensitive children were more likely at six to be more socially competent than others. So that is a clear example of differential susceptibility—a negative environment leads to a negative result, but a positive environment leads to a positive result, but only for highly sensitive children. The others were hardly affected by their parenting (no parents in the study were abusive.)

Bottom Line:  Just more evidence that HSCs with a good-enough childhood can truly shine. The others will do fine with time and maybe some help.

The next study came out in 2021, but is from the same longitudinal study so I include it here:

The role of environmental sensitivity in the development of rumination and depressive symptoms in childhood: a longitudinal study

Citation:  Lionetti, F., Klein, D. N., Pastore, M., Aron, E. N., Aron, A., & Pluess, M. (2021). The role of environmental sensitivity in the development of rumination and depressive symptoms in childhood: a longitudinal study. European Child & Adolescent Psychiatry, 1-11.

In the study above, published earlier, the three-year-olds assessed for sensitivity were tested again at six, and the highly sensitive children with permissive parents had more problems, while those whose parents were using an “authoritative” style demonstrated more social competence than other children.

Now, in this study, with the children aged nine, highly sensitive children with permissive parenting were still doing poorly, although the positive effects of authoritative parenting did not show up.  The sensitive children at nine with permissive parenting scored higher on a questionnaire about how much they ruminated (dwelled on negative thoughts; they were now old enough to ask) and scoring higher on rumination in turn tended to predict their being depressed at that age and did so to a lesser extent when they were tested again at age twelve.  All in all, permissive parenting in this study was a problem for sensitive children.  One might wonder whether “permissive” was a sign of parents being indifferent to their children, which sensitive children would notice more than others.  Or it could be that sensitive children need help understanding and regulating their emotions while young, and without that they are more troubled by negative feelings.

Bottom Line: Again, being highly sensitive means that how you were parented affected you more when you were a child and probably still does in adulthood.  You might want to consider the type of parent you had:  Permissive, authoritative (firm boundaries but listened to you with respect), or authoritative (simply strict) and consider how this has shaped you.

Sensory Processing Sensitivity in the context of Environmental Sensitivity: A critical review and development of research agenda

Citation:  Greven, C. U., Lionetti, F., Booth, C., Aron, E. N., Fox, E., Schendan, H. E., … & Homberg, J. (2019). Sensory processing sensitivity in the context of environmental sensitivity: A critical review and development of research agenda. Neuroscience & Biobehavioral Reviews, 98, 287-305.

You have been warned:  This is a long, complicated review of all the research.  However, it does review every study up to 2019, and discusses important matters, such as how SPS relates to other theories and other temperament and personality traits, the possible underlying causes of the trait, its “neurobiological mechanisms,” and its relations to various mental and sensory disorders.  Good luck!

Bottom Line:  There are enough studies now to permit the publication of a lengthy review of the research on HSPs.