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The Birth of the Research on High Sensitivity

10th April 2020 - By Elaine N. Aron

About the authors

Elaine N. Aron, Ph.D. has studied sensitivity since 1990.  She has also written, among others, The Highly Sensitive Person (in 32 languages), The Highly Sensitive Child, The Highly Sensitive Parent, and Psychotherapy and the Highly Sensitive Person. She and her husband are also well-known for their study of close relationships.


The study of high sensitivity began with curiosity about the casual use of the term “sensitive” among psychologists. It led to interviews, and based on these, to the 27-item Highly Sensitive Person Scale.  It includes a wide variety of items all statistically closely associated, suggesting an underlying innate trait.

Background information

The concept of high sensitivity was born out of extensive research that began in 1990 and was finally published in 1997, in one of the most respected journals publishing research on personality[1].

The research began when I became curious about the use of “sensitive” or “highly sensitive” as a casual descriptor found in case studies of patients.  Doing a literature search, I found it used to refer to gifted individuals and to effective parents.  Further, something like it was identified in infants as young as 3 months and in many species of animals.

How the study was conducted

Although it is not common now to begin research with qualitative interviews, it has long been recommended by methodologists [2].

Letting my curiosity take me another step, I interviewed persons who saw themselves as “highly sensitive,” recruiting from psychology classes at the University of California, Santa Cruz; in the campus staff newsletter; and in a local arts association newsletter, asking for those seeing themselves as  either “highly introverted” or “easily overwhelmed by stimulation.”

Introversion was emphasized because at the time (not now) introversion was seen as mostly a greater sensitivity to stimuli and I thought sensitivity might simply be another term for introversion.

After accepting the first 30 who seemed to understand what I was looking for, I added 10 more to make the total reasonably representative.  In the end 39 people were interviewed: 12 students, 17 men, 30 single (8 of whom were divorced).  One of each sex was homosexual. Ages ranged from 18 to 66, with at least 4 in each decade.

Qualitative interviews

The interviews were 2-3 hours, and began with questions about how they understood the announcement’s description of sensitivity, then moved from less personal (e.g. favorite entertainment and preferred environments) to more personal (first memories, relationships with parents, school life, friendships, dating and romance or marriage, work life, and philosophical or religious views).

Immediately after each interview respondents answered a brief questionnaire about adult attachment style [3], because attachment to a caregiver in early life—secure about closeness, anxious about it, or avoiding it—can greatly affect adult behavior.  They also took the Myers Briggs Type Indicator [4], a measure of introversion.

Key findings

I found that half had already thought considerably about being highly sensitive.  For the others, it was entirely new.  Of the 38 who completed the attachment questionnaire, 12 chose secure; 15, avoidant; 4, anxious ambivalent; and 5 were undecided.  Of the 35 who completed the MBTI, 7 were extraverted, which was striking since I explicitly asked for introverts.  Yet they were clearly highly sensitive.

Fitting with the impression that this was an inherited trait, there was a wide range of personal histories, not a single pattern.  Many had good childhoods, were generally successful, and saw considerable advantages to their sensitivity, although their lives had been greatly shaped by it.  Those with worse childhoods were struggling more in life and saw their sensitivity more as a problem or flaw.

Development of the first sensitivity measure

At this point my husband, an expert in statistical methods, collaborated with me to create a measure of high sensitivity based on common responses in the interviews.

For example, “Do you find yourself needing to withdraw during busy days …where you can have …relief from stimulation?”  Other examples of items based on the interviews were about startling easily and sensitivity to caffeine, loud noises, pain, and hunger. We also included items about introversion, childhood struggles, anxiety, and depression, to find the relationship of these to sensitivity.

A good measure is of only one thing, so we eliminated items that were not strongly associated with each other. Plus one looks for its relation to other variables.

To do the necessary research on this, we administered the measure to 1004 university students in 11 classes around the country, plus 299 in the Santa Cruz community reached by random-digit-dialing of telephones.

At the end of the research, there was still a wide variety of items strongly associated with each other, ranging from a rich, complex inner life to being nervous when being observed while performing a task.

This variety points to an underlying trait affecting many aspects of life.  And every item on the final 27-item HSP Scale that survived this scrutiny was based on the interviews.

General conclusions

To conclude, this research did not “discover a new trait,” but one that needed a more accurate name than “shyness,” “neuroticism,” “inhibitedness,” or “introversion.” Nor was it done in order to write a self-help book—that was not my plan and came later.  It all began out of simple curiosity about our use of a common word.


  1. Aron, E.N. and A. Aron, Sensory-processing sensitivity and its relation to introversion and emotionality. J Pers Soc Psychol, 1997. 73(2): p. 345-68.
  2. Campbell, D.T., Social Research and Public Policies. 1975, Hanover, New Hampshire: University Press of New England.
  3. Hazan, C. and P.R. Shaver, Romantic Love Conceptualized as an Attachment Process. Journal of Personality and Social Psychology, 1987. 52: p. 511-524.
  4. Myers, I.B., The Myers-Briggs Type Indicator: Manual (1962). 1962: Counseling Psychologists Press.