Genetic Factors Make Some of Us More Sensitive Than Others

A study suggests that differences in sensitivity are partly rooted in our genes.

Posted Jun 04, 2020

mcmurryjulie/Pixabay
Source: mcmurryjulie/Pixabay

New research on the genetic underpinnings of sensitivity suggests that about half of the differences between people on this characteristic could be attributable to genes. The findings of this study (Assary et al., 2020) were published on June 3 in the journal Molecular Psychiatry.

Although this study is multi-faceted, the researchers' primary focus was to investigate the genetic architecture of sensitivity in identical and non-identical twins and to identify if the human trait of sensitivity has a genetic basis. 

Varying degrees of sensitivity were measured using the Highly Sensitive Child (HSC) questionnaire, which is a 12-item questionnaire specifically designed to measure sensitivity in children and adolescents. This HSC scale was introduced two years ago in a Developmental Psychology paper (Pluess et al., 2018) that identified varying degrees of environmental sensitivity (ES) in a cohort of 3,581 children and adolescents (aged 8–19) residing in the United Kingdom.

The most recent UK-based study (2020) on the "heritability of sensitivity" by researchers at Queen Mary University of London and Kings College London compared 2,868 adolescent twins. As mentioned, their primary goal was to identify how much of the variation in human sensitivity is linked to genetics vs. non-genetic influences.

For all intents and purposes, the results of this investigation into the heritability of sensitivity suggest that the split is roughly 50/50. As the authors explain:

"[We] found that genetic influences accounted for 47% of the variation in sensitivity, while non-shared environmental influences and measurement error accounted for the remaining 53% of the variance. Our results support theories proposing that sensitivity is a heritable trait, whereby genetic variation explains nearly half of the observed individual differences in sensitivity."

"We are all affected by what we experience—sensitivity is something we all share as a basic human trait. But we also differ in how much of an impact our experiences have on us," lead author Michael Pluess, professor of developmental psychology at QMUL, said in a June 3 news release.

He added: "Scientists have always thought there was a genetic basis for sensitivity, but this is the first time we've been able to actually quantify how much of these differences in sensitivity are explained by genetic factors."

The researchers also explored the interplay between the genetic aspects of sensitivity and the Big Five personality traits of agreeableness, conscientiousness, extraversion, neuroticism, and openness.  

Notably, they found that genetic components of sensitivity were moderately correlated with higher neuroticism and lower extraversion. The authors explain how the genetics of sensitivity and aspects of the Big Five are correlated:

"The majority of the heritability of sensitivity was explained by genetic factors that also influence neuroticism, and to a lesser extent extraversion. A small proportion of the variance in sensitivity was explained by genetic factors that are specific to sensitivity. However, we found no evidence that environmental influences that are involved in the prediction of the Big Five personality traits are also relevant for variation in sensitivity."

This study on the heritability of sensitivity has several strengths but also has limitations. Two strengths are that this is the first large, representative study to identify a genetic basis for the human trait of sensitivity and to examine the connection between the heritability of sensitivity and the Big Five personality traits.

Regarding the limitations of this study: The "heritability of sensitivity" estimate of 47 percent is only based on a cohort of adolescent twins. "Therefore, it cannot be assumed that the same estimates will necessarily apply to environmental sensitivity studies that feature infants and toddlers. Furthermore, it must be acknowledged that the obtained estimates are specific to the [HSC] measure that we used," the authors state.

Michael Pluess is optimistic that these findings have the potential to improve how we handle environmental sensitivity in ourselves and those around us. "Because we now know that this sensitivity is as much due to biology as environment, it is important for people to accept their sensitivity as an important part of who they are and consider it as a strength, not just as a weakness," he concluded.

References

Elham Assary, Helena M. S. Zavos, Eva Krapohl, Robert Keers, Michael Pluess. "Genetic Architecture of Environmental Sensitivity Reflects Multiple Heritable Components: A Twin Study With Adolescents." Molecular Psychiatry (First published: June 03, 2020) DOI: 10.1038/s41380-020-0783-8

Michael Pluess, Elham Assary, Francesca Lionetti, Elham Lester, Eva Krapohl, Elaine N. Aron, Arthur Aron. "Environmental Sensitivity in Children: Development of the Highly Sensitive Child Scale and Identification of Sensitivity Groups." Developmental Psychology (First published: January 2018) DOI: 10.1037/dev0000406