Sensitivity is a basic trait. It’s defined as the ability to perceive and process information about the environment. All people are sensitive but some considerably more than others. A new study published in the Journal of Molecular Psychiatry examined the genetic architecture of environmental sensitivity using a sample of 2868 adolescent twins.
“We investigated to what degree genetic versus environmental factors contribute to the human trait of sensitivity,” study author Michael Pluess told us. “We aimed to investigate to what degree genetic factors contribute to such differences and whether these genetic components overlap with those of other established personality traits.”
Twins help researchers with studies involving genes and environmental factors. They can be done on fraternal or identical twins. Twins are usually used in psychological or biological studies. Studies with twins are useful to researchers because twins share 100 per cent of their genes. That means, any differences between the twins are due to outside influences.
Pluess is a professor of developmental psychology at the Department of Biological and Experimental Psychology at Queen Mary University of London. Pluess and his team of researchers measured sensitivity with a validated questionnaire on sensitivity which they developed. Based on theoretical considerations, they hypothesized that sensitivity would have a considerable heritability, that it would reflect a single component of sensitivity and that it would share some of its heritability with common personality traits.
“Sensitivity is a relatively new concept in psychology,” Pluess told us. “Although it is assumed by many that genetic factors play a role in sensitivity, its heritability has not been formally assessed yet. Hence, first results on the heritability of sensitivity would guide future work on the genetic and environmental factors that contribute to differences in sensitivity and significantly advance our knowledge on sensitivity.”
Researchers applied classic twin methodology to estimate the degree to which genetic and environmental factors contribute to differences in sensitivity between people.
“We found that 47 per cent of differences in sensitivity between people is explained by genetic factors and the remaining 53 per cent by environmental factors,” Pluess told us. “This means that genetic factors are as important as environmental factors.:
Pluess and his team also found that there are three relatively independent genetic components of sensitivity: One general one, one that is associated with sensitivity to more negative experiences, and one associated with sensitivity to more positive experiences. In addition, they found that the genetic components of sensitivity overlaps substantially with the genetic component of neuroticism and to a lesser degree with extraversion.
“A heritability of 47 per cent is relatively normal for personality traits,” Pluess told us. “What we didn’t know in advance is whether sensitivity would be made up of one or multiple genetic components. The findings that the heritability of sensitivity to negative experiences differs from sensitivity to positive experiences was somewhat surprising. The associations with personality traits are interesting but in line with previous work we conducted.”
The results suggest that one of the reasons that people differ in their sensitivity, is that they differ in their genetic make-up. The fact that the heritability is relatively large with 47 per cent means that there is scope to investigate the specific genes involved in sensitivity through molecular studies.
“The fact that more than half of the differences are explained by environmental factors (i.e., nurture) suggests that sensitivity is not just a given but develops in response to what people experience,” Pluess told us. “We need to also try to identify what specific experiences contribute to people’s individual levels of sensitivity.”
Patricia Tomasi is a mom, maternal mental health advocate, journalist, and speaker. She writes regularly for the Huffington Post Canada, focusing primarily on maternal mental health after suffering from severe postpartum anxiety twice. You can find her Huffington Post biography here. Patricia is also a Patient Expert Advisor for the North American-based, Maternal Mental Health Research Collective and is the founder of the online peer support group - Facebook Postpartum Depression & Anxiety Support Group - with over 1500 members worldwide. Blog: www.patriciatomasiblog.wordpress.com