Sensory Processing Sensitivity: Trait, Scientific Evidence, and Clinical Implications
Article written in collaboration with @marta.spaziopsico
Introduction
In everyday language, "you're too sensitive" often sounds like a reproach. In psychology, however, sensitivity is an object of study with its own theoretical history, measurement tools, and open debate. This article reconstructs the construct of Sensory Processing Sensitivity (SPS), discusses its empirical foundations and limitations, and draws some implications for clinical practice and for the well-being of highly sensitive people (HSPs).
1. Origins of the Construct
The concept of high sensitivity was formalized by Aron and Aron (1997), who described SPS as a stable individual difference in the way the nervous system registers and processes stimuli. The authors started from an observation: some people seem to "pause to check" before acting, notice what others miss, and become overwhelmed more easily in highly stimulating environments.
Aron and Aron (1997) also distinguished SPS from two constructs with which it is often confused: introversion and negative emotionality (akin to neuroticism). Sensitivity is correlated with both, but coincides with neither. This finding is central to dispelling a widespread misunderstanding, namely that "sensitive" means "shy" or "anxious."
Aron's (1996) popular book subsequently made the trait known to the general public, introducing the estimate that about 20% of the population is highly sensitive.
2. The Theoretical Framework: Environmental Sensitivity and Differential Susceptibility
Today SPS is placed within a broader framework, that of environmental sensitivity. According to this perspective, individuals differ in the extent to which they are influenced by environmental experiences, both positive and negative (Pluess, 2015).
The framework rests on three related models:
Biological sensitivity to context. Boyce and Ellis (2005) proposed that heightened stress reactivity, often read as vulnerability, may serve an adaptive function: in very favorable or very adverse environments, being more sensitive to context offers advantages.
Differential susceptibility. Belsky and Pluess (2009) argue that some individuals are more affected than others by both unfavorable and favorable contexts. Ellis et al. (2011) proposed an evolutionary and neurobiological interpretation of this model.
Vantage sensitivity. Pluess and Belsky (2013) showed that some people benefit more from positive experiences and supportive interventions. This is a crucial point for clinical practice: sensitivity is not only a risk factor, but also a resource for change.
Within this framework, high sensitivity is not a "factory defect" but a strategy of response to the environment, with costs and benefits that depend on context.
3. The Components of the Trait
3.1 The DOES Model
Aron et al. (2012) summarize the characteristics of SPS with the acronym DOES:
Depth of processing: deeper processing of information, with a greater tendency to reflect and to link new information to existing knowledge.
Overstimulation: greater susceptibility to overstimulation, a logical consequence of more intense perception and processing.
Emotional reactivity and empathy: more intense emotional responses and greater attunement to others' emotional states.
Sensitivity to subtleties: the ability to pick up on subtle nuances and changes in the environment.
3.2 Factor Structure
From a psychometric standpoint, the structure is less straightforward than the DOES model suggests. Smolewska et al. (2006) analyzed the Highly Sensitive Person Scale (HSPS) and identified three factors: ease of excitation, aesthetic sensitivity, and low sensory threshold. These factors do not correlate uniformly with other personality dimensions and with well-being: in particular, ease of excitation and low sensory threshold tend to be associated with greater distress, whereas aesthetic sensitivity has a more "positive" profile.
This finding has a practical consequence: not all highly sensitive people are sensitive in the same way, and the total score conceals different profiles.
4. Prevalence: Category or Continuum?
Aron (1996) estimated a prevalence of 20%, with the majority of HSPs being introverted (about 70%) and a minority being extraverted. The figure entered common parlance, but subsequent research has shown that it depends on how the trait is defined.
Lionetti et al. (2018) applied latent class analysis to samples of adults and children and identified three groups: low sensitivity (about 30%), medium sensitivity (about 40%), and high sensitivity (about 30%). The authors made them famous with the metaphor of dandelions, tulips, and orchids. Pluess et al. (2018), using the Highly Sensitive Child Scale, obtained a similar division, with a share of highly sensitive children of around one third of the sample.
It is worth being honest about one limitation. The division into groups is a way of describing a continuum, and the thresholds are partly conventional. For this reason, the percentages should be presented as estimates and not as definitive epidemiological data (Greven et al., 2019).
5. Origins: Genetics and Environment
The trait has a heritable component. In a twin study of adolescents, Assary et al. (2021) estimated that environmental sensitivity is substantially influenced by genetic factors (around half of the variance) and that there are multiple distinct heritable components, consistent with the idea of a multidimensional trait. The remaining contribution is attributable to the non-shared environment, meaning that different life experiences shape the expression of the trait even in genetically similar individuals.
It should be added that research on specific candidate genes (for example, the serotonin transporter gene) has produced heterogeneous results that have generally not been robustly replicated, and Greven et al. (2019) call for caution on this front.
6. Neural Bases
Neuroimaging research on SPS is still limited, but consistent with the theoretical model.
Jagiellowicz et al. (2011) found that participants with higher SPS scores showed greater activation of visual and attentional areas when detecting subtle differences between visual scenes.
Acevedo et al. (2014) observed, in highly sensitive people, greater activation of regions linked to awareness, empathy, and sensory processing while viewing faces expressing emotions, particularly when the faces were those of loved ones.
The samples are small and the experimental designs limited, so the results should be considered preliminary. Greven et al. (2019) stress the need for larger, replicated studies before speaking of a true "neural signature" of the trait.
7. Sensitivity, Mental Health, and Work
7.1 The Risk
HSPs show, on average, higher levels of anxiety and depressive symptoms (Liss et al., 2008). Regarding physical health and perceived stress, Benham (2006) found greater reporting of somatic symptoms and stress. In the workplace, Evers et al. (2008) found that high SPS is associated with higher levels of stress and fatigue symptoms, presumably due to greater exposure to stimuli and demands.
7.2 How to Interpret These Data
It is not correct to conclude that HSPs are "more fragile." The associations with distress emerge mainly in unfavorable contexts, such as stressful environments, difficult childhoods, or excessive workloads. Within the framework of differential susceptibility, the same individuals are also those who respond best to supportive environments and psychological interventions. Pluess and Boniwell (2015), for example, showed that more sensitive adolescents benefit more from a school-based depression prevention program.
There is also a problem of conceptual overlap: some HSPS items describe distress reactions and may artificially inflate the association with anxiety and depression. This too is a point on which the critical literature urges caution (Greven et al., 2019).
8. Limitations and Open Questions
An honest article on high sensitivity must also give space to criticism. Greven et al. (2019) point out several issues:
Measurement: research relies largely on self-report questionnaires, with possible biases and overlap with other traits.
Distinction from other constructs: unclear boundaries with neuroticism, introversion, behavioral inhibition, and autism spectrum traits (Liss et al., 2008).
Prevalence: estimates vary depending on methods, with no clinically validated threshold.
Neurobiological evidence: still scarce and based on small samples.
Status of the trait: SPS is not a diagnosis and does not appear in diagnostic manuals; it is considered a temperamental trait and not a clinical condition.
These limitations do not invalidate the construct, but they indicate that science communication should avoid absolute claims.
9. Implications for Practice
The following indications derive from the literature and from a reasoned extension of its principles. To date, there is no SPS-specific therapeutic protocol validated by controlled studies, so they should be understood as general guidelines.
Psychoeducation and normalization. Explaining the trait as a normal variation, not as a pathology, can reduce the perception of "being wrong." It is often the first intervention and one of the most effective.
Managing overstimulation. Regulating loads (rhythms, commitments, environments), and planning breaks and recovery time after demanding situations.
Boundaries and assertiveness. Learning to recognize one's limits and to communicate them, since high empathy exposes people to the risk of taking on others' needs at the expense of their own.
Emotion regulation. Practices such as mindfulness are promising; Bakker and Moulding (2012) observed that dispositional mindfulness plays a protective role in the relationship between SPS and negative psychological symptoms.
Choosing and building contexts. If sensitivity amplifies the effect of the environment, the quality of contexts (work, relationships, spaces) becomes a health factor in its own right.
Valuing resources. Depth of thought, attention to detail, empathy, and aesthetic sensitivity are skills that can be put to use in many personal and professional domains.
Specialist consultation. When overstimulation is accompanied by significant distress, persistent anxiety, or low mood, it is advisable to consult a professional, so that other underlying conditions can also be assessed.
Conclusions
High sensitivity is a documented trait, with genetic bases, preliminary neural correlates, and a solid theoretical framework in environmental sensitivity. It is not an illness, and its most up-to-date reading is neither "vulnerability" nor "superpower": it is a greater permeability to the environment, which amplifies both the effects of unfavorable contexts and the benefits of favorable ones. Open questions remain regarding prevalence, measurement, boundaries with other constructs, and biological mechanisms. For those working in the helping professions, the challenge is to help people recognize the trait without pathologizing or idealizing it.
References
Acevedo, B. P., Aron, E. N., Aron, A., Sangster, M.-D., Collins, N., & Brown, L. L. (2014). The highly sensitive brain: An fMRI study of sensory processing sensitivity and response to others' emotions. Brain and Behavior, 4(4), 580–594. https://doi.org/10.1002/brb3.242
Aron, E. N. (1996). The highly sensitive person: How to thrive when the world overwhelms you. Carol Publishing Group.
Aron, E. N., & Aron, A. (1997). Sensory-processing sensitivity and its relation to introversion and emotionality. Journal of Personality and Social Psychology, 73(2), 345–368. https://doi.org/10.1037/0022-3514.73.2.345
Aron, E. N., Aron, A., & Jagiellowicz, J. (2012). Sensory processing sensitivity: A review in the light of the evolution of biological responsivity. Personality and Social Psychology Review, 16(3), 262–282. https://doi.org/10.1177/1088868311434213
Assary, E., Zavos, H. M. S., Krapohl, E., Keers, R., & Pluess, M. (2021). Genetic architecture of environmental sensitivity reflects multiple heritable components: A twin study with adolescents. Molecular Psychiatry, 26, 4896–4904.
Bakker, K., & Moulding, R. (2012). Sensory-processing sensitivity, dispositional mindfulness and negative psychological symptoms. Personality and Individual Differences, 53(3), 341–346.
Belsky, J., & Pluess, M. (2009). Beyond diathesis stress: Differential susceptibility to environmental influences. Psychological Bulletin, 135(6), 885–908. https://doi.org/10.1037/a0017376
Benham, G. (2006). The highly sensitive person: Stress and physical symptom reports. Personality and Individual Differences, 40(7), 1433–1440.
Boyce, W. T., & Ellis, B. J. (2005). Biological sensitivity to context: I. An evolutionary–developmental theory of the origins and functions of stress reactivity. Development and Psychopathology, 17(2), 271–301. https://doi.org/10.1017/S0954579405050145
Ellis, B. J., Boyce, W. T., Belsky, J., Bakermans-Kranenburg, M. J., & van IJzendoorn, M. H. (2011). Differential susceptibility to the environment: An evolutionary–neurodevelopmental theory. Development and Psychopathology, 23(1), 7–28. https://doi.org/10.1017/S0954579410000611
Evers, A., Rasche, J., & Schabracq, M. J. (2008). High sensory-processing sensitivity at work. International Journal of Stress Management, 15(2), 189–198. https://doi.org/10.1037/1072-5245.15.2.189
Greven, C. U., Lionetti, F., Booth, C., Aron, E. N., Fox, E., Schendan, H. E., Pluess, M., Bruining, H., Acevedo, B., Bijttebier, P., & 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. https://doi.org/10.1016/j.neubiorev.2019.01.009
Jagiellowicz, J., Xu, X., Aron, A., Aron, E., Cao, G., Feng, T., & Weng, X. (2011). The trait of sensory processing sensitivity and neural responses to changes in visual scenes. Social Cognitive and Affective Neuroscience, 6(1), 38–47. https://doi.org/10.1093/scan/nsq001
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, Article 24. https://doi.org/10.1038/s41398-017-0090-6
Liss, M., Mailloux, J., & Erchull, M. J. (2008). The relationships between sensory processing sensitivity, alexithymia, autism, depression, and anxiety. Personality and Individual Differences, 45(3), 255–259. https://doi.org/10.1016/j.paid.2008.04.009
Pluess, M. (2015). Individual differences in environmental sensitivity. Child Development Perspectives, 9(3), 138–143. https://doi.org/10.1111/cdep.12120
Pluess, M., Assary, E., Lionetti, F., Lester, K. J., Krapohl, E., Aron, E. N., & Aron, A. (2018). Environmental sensitivity in children: Development of the Highly Sensitive Child Scale and identification of sensitivity groups. Developmental Psychology, 54(1), 51–70. https://doi.org/10.1037/dev0000406
Pluess, M., & Belsky, J. (2013). Vantage sensitivity: Individual differences in response to positive experiences. Psychological Bulletin, 139(4), 901–916. https://doi.org/10.1037/a0030196
Pluess, M., & Boniwell, I. (2015). Sensory-processing sensitivity predicts treatment response to a school-based depression prevention program: Evidence of vantage sensitivity. Personality and Individual Differences, 82, 40–45.
Smolewska, K. A., McCabe, S. B., & Woody, E. Z. (2006). A psychometric evaluation of the Highly Sensitive Person Scale: The components of sensory-processing sensitivity and the relationship of the BIS/BAS and "Big Five". Personality and Individual Differences, 40(6), 1269–1279. https://doi.org/10.1016/j.paid.2005.09.022
Comments