Highly Sensitive Person Scale (HSP Scale)

Abstract

The Highly Sensitive Person Scale (HSP Scale) is a 27-item self-report psychometric instrument designed to measure Sensory Processing Sensitivity (SPS) in adult populations. Formulated by psychologists Elaine N. Aron and Arthur Aron in 1997, the scale operationalizes SPS as a genetically informed, phenotypic temperament trait characterized by heightened central nervous system sensitivity to environmental, social, and internal stimuli. The questionnaire employs a 7-point Likert response scale ranging from 1 (“Not at all”) to 7 (“Extremely”), anchored at the midpoint by 4 (“Moderately”). Although originally posited as a unidimensional construct reflecting general environmental sensitivity, subsequent psychometric investigations across diverse cultures and clinical cohorts have predominantly demonstrated a multidimensional architecture, most commonly reflecting three correlated yet distinct first-order factors: Ease of Excitation (EOE), Low Sensory Threshold (LST), and Aesthetic Sensitivity (AES), structured beneath a higher-order general sensitivity dimension. Across extensive international replications, the HSP Scale demonstrates robust psychometric properties, consistently yielding internal consistency estimates (Cronbach’s alpha and McDonald’s omega) between .85 and .89 for the total score, alongside satisfactory test-retest reliability ($r = .70$ to $.85$). Construct, convergent, and discriminant validity have been confirmed through rigorous associations with the Five-Factor Model (notably Neuroticism and Openness to Experience), Gray’s Behavioral Inhibition System (BIS), and behavioral tasks assessing sensory discrimination and emotional reactivity. Furthermore, neuroimaging and physiological investigations affirm its validity by linking higher HSP Scale scores to differential activation in brain regions implicated in empathy, awareness, and sensory integration, such as the insula, anterior cingulate cortex, and the mirror neuron system. This article provides an exhaustive psychometric overview of the HSP Scale, detailing its theoretical foundation, structural validity, scoring protocols, and empirical applications.

Keywords

Highly Sensitive Person Scale, Sensory Processing Sensitivity, Environmental Sensitivity, Differential Susceptibility, Ease of Excitation, Low Sensory Threshold, Aesthetic Sensitivity, Temperament, Neuroticism, Psychometrics

Authors

The Highly Sensitive Person Scale was developed by Elaine N. Aron, Ph.D., and Arthur Aron, Ph.D.

Elaine N. Aron, Ph.D., is an American research and clinical psychologist renowned for her pioneering work on sensory processing sensitivity and temperament. She conducted her doctoral work at the Pacifica Graduate Institute and completed extensive clinical and research fellowships focusing on personality architecture, intimate relationships, and depth psychology. She has served as an independent researcher and research associate in the Department of Psychology at the State University of New York at Stony Brook (Stony Brook University).

Arthur Aron, Ph.D., is a distinguished Research Professor of Psychology at Stony Brook University and a Visiting Scholar at the University of California, Berkeley. He is an internationally recognized social psychologist specializing in close relationships, interpersonal attraction, group dynamics, and the neural substrates of love and motivation. His methodological expertise was instrumental in the psychometric formulation and statistical validation of the original HSP Scale.

Correspondence regarding the original scale validation was historically directed to the Department of Psychology, State University of New York at Stony Brook, Stony Brook, NY 11794.

Purpose

The primary purpose of the Highly Sensitive Person Scale is to measure the degree of Sensory Processing Sensitivity (SPS) in adults, capturing individual differences in neurocognitive processing depth, environmental reactivity, and sensory threshold. Sensory Processing Sensitivity represents a fundamental personality and temperament trait observed in roughly 15% to 30% of human populations, as well as in over 100 non-human animal species. The trait describes an evolutionary adaptation favoring deep information processing before taking action, rather than immediate reactivity.

In empirical research, the HSP Scale serves as an essential tool to investigate the overarching paradigm of Environmental Sensitivity, which encompasses theories such as Differential Susceptibility Theory (Belsky & Pluess) and Biological Sensitivity to Context (Boyce & Ellis). The instrument allows scientists to examine why certain individuals disproportionately suffer adverse psychological outcomes in unsupportive or chaotic environments, while simultaneously deriving disproportionately greater developmental, emotional, and social benefits from enriched, supportive, and therapeutic environments—a phenomenon known as vantage sensitivity.

In clinical, counseling, and applied organizational settings, the HSP Scale addresses several critical diagnostic and therapeutic needs:

• Differential Diagnosis and De-pathologization: The scale differentiates innate sensory sensitivity from clinical disorders that share superficial behavioral markers, such as Social Anxiety Disorder, Autism Spectrum Conditions, Attention Deficit Hyperactivity Disorder (ADHD), and Generalized Anxiety Disorder. Unlike neurodevelopmental impairments or mood pathologies, high SPS represents a normal, evolutionary preserved variation of human temperament. Administering the scale assists clinicians in de-pathologizing clients who have historically been mislabeled as chronically neurotic, hypochondriacal, or avoidant.
• Preventative Psychological Intervention: Individuals scoring high on the HSP Scale are prone to sensory overstimulation, cognitive fatigue, and burnout when operating in chronically overstimulating work or domestic environments. Identifying this trait allows therapists, counselors, and executive coaches to formulate environmental modifications, sensory modulation strategies, and tailored stress-reduction routines.
• Maximizing Aesthetic and Social Strengths: Beyond measuring vulnerabilities to sensory overload, the instrument highlights positive attributes, including high empathy, rich inner experience, appreciation for the arts, and heightened discernment of social subtleties, enabling individuals to cultivate vocational niches that align with their cognitive-affective profiles.

Psychological Construct

The psychological construct operationalized by the HSP Scale is Sensory Processing Sensitivity (SPS). Sensory Processing Sensitivity is conceptualized not as a sensory organ acuity (i.e., it does not denote superior visual acuity or exceptional decibel detection at the level of the peripheral receptors), but rather as an enhanced central nervous system capacity to perceive, register, and elaborate upon environmental information. Aron and colleagues synthesize the construct under the theoretical acronym DOES:

• D — Depth of Processing: A foundational tendency to process sensory information more deeply and elaborately at cognitive, semantic, and neurobiological levels. Highly sensitive individuals engage extensive cognitive architecture to compare current inputs with past experiences, leading to prolonged observation and deliberation before executing behavioral responses.
• O — Overstimulation (Overarousal): Because the sensory and neural filters admit a wider spectrum and greater volume of stimuli, highly sensitive individuals reach their cognitive and physiological capacity more rapidly than less sensitive peers. Prolonged immersion in chaotic, loud, or fast-paced settings precipitates acute autonomic arousal, cognitive fatigue, and an urgent necessity for social and sensory withdrawal.
• E — Emotional Reactivity and Empathy: Individuals with high SPS display intensified emotional responses to both valence extremes (positive and negative stimuli). They exhibit higher activation in neural regions supporting empathy, emotional resonance, and theory of mind, rendering them exceptionally attuned to the subjective affective states of others.
• S — Sensing Subtleties: A pronounced perceptual awareness of subtle environmental stimuli that escape the notice of standard observers. This encompasses faint odors, nuanced vocal inflections, micro-expressions, delicate textures, ambient acoustic shifts, and minor physical discrepancies in spatial layouts.

Extensive psychometric investigations (e.g., Smolewska, McCabe, & Woody, 2006) demonstrate that although SPS functions as an integrated macro-construct, its operational representation within the HSP Scale reflects three robust, interrelated sub-dimensions:

1. Ease of Excitation (EOE)

Ease of Excitation captures an individual’s vulnerability to becoming mentally rattled, overwhelmed, and cognitively disorganized in the presence of excessive external demands, rapid task switching, multitasking pressures, or intense environmental stimulation. Prototypic items assessing EOE include feeling overwhelmed when asked to do too many things at once, experiencing severe distress during chaotic time-pressured tasks, or feeling profoundly shaken by life transitions.

2. Low Sensory Threshold (LST)

Low Sensory Threshold indexes physiological and psychological discomfort triggered by intense sensory inputs across sensory modalities. This includes acute aversion to loud noises, bright or flickering lights, coarse tactile fabrics, strong odors, and chaotic visual scenes. Individuals high in LST frequently implement active environmental coping mechanisms to mitigate sensory inundation, such as avoiding violent media or retreating into dark, quiet spaces.

3. Aesthetic Sensitivity (AES)

Aesthetic Sensitivity reflects the positive, enriching facets of SPS. It measures an individual’s capacity to be deeply moved by music, visual arts, and poetic expressions, alongside a heightened enjoyment of delicate tastes, scents, and harmonic aesthetics. AES also captures the presence of a rich, complex inner life, contemplative introspection, and acute awareness of subtle beauty in everyday surroundings.

Theoretical Framework

The theoretical framework underpinning the HSP Scale synthesizes principles from evolutionary biology, developmental psychopathology, and human behavioral genetics. The scale originated within Elaine Aron’s integrative review of temperament literature, specifically examining Pavlov’s research on the transmarginal inhibition of the nervous system, Thomas and Chess’s longitudinal models of temperament reactivity and threshold, and Jerome Kagan’s paradigms on behavioral inhibition.

Evolutionary Conservation of Sensory Sensitivity

The central evolutionary postulate advanced by Aron and Aron (1997), and later supported by theoretical models (e.g., Wolf, van Doorn, & Leimar, 2008), posits that within any given social species, a stable minority exhibits a “responsive” or “sensitive” strategy (processing contextual cues thoroughly to maximize fitness opportunities and minimize fatal risks), while the majority adopts an “unresponsive” strategy (acting rapidly without extensive environmental scanning). Neither strategy is uniformly superior; rather, frequency-dependent selection maintains both phenotypes within the gene pool. In benign or resource-rich environments, deep processors detect hidden opportunities; in perilous contexts, their vigilance prevents catastrophic errors. Conversely, in volatile conditions requiring rapid reflexive action, the less sensitive phenotype experiences an evolutionary advantage.

Environmental Sensitivity and Vantage Sensitivity

Modern conceptualizations frame the HSP Scale within the overarching umbrella of Environmental Sensitivity (Pluess, 2015). Historically, psychological literature viewed heightened biological and temperamental reactivity strictly through a diathesis-stress model, characterizing sensitive individuals as fragile, vulnerable, and prone to psychopathology under stress. While individuals with high SPS do indeed exhibit heightened vulnerability when reared in adverse, neglectful, or abusive conditions (manifesting as elevated rates of depression, anxiety, and somatic complaints), the HSP theoretical framework embraces Differential Susceptibility Theory (Belsky & Pluess, 2009) and Biological Sensitivity to Context (Boyce & Ellis, 2005). These frameworks demonstrate that sensitive individuals are not merely “vulnerable” but “plastic”—they show superior developmental and psychological outcomes when supported by warm, enriching, and attuned environments, outpacing low-sensitivity individuals in positive adaptation, empathy, and academic or vocational flourishing.

Neurobiological and Physiological Foundations

The construct measured by the HSP Scale is supported by empirical findings across neuroimaging (fMRI), electroencephalography (EEG), and genetic studies:

• Neural Correlates of Empathy and Awareness: Functional neuroimaging studies (Acevedo et al., 2014, 2018) show that when exposed to images of their partners’ or strangers’ emotional facial expressions (both happy and sad), individuals scoring high on the HSP Scale display significantly greater blood-oxygen-level-dependent (BOLD) responses in the anterior insula, ventral tegmental area (VTA), premotor cortex, and inferior frontal gyrus (components of the mirror neuron system). The anterior insula is intimately linked to subjective conscious awareness and integration of internal physiological states with external social cues.
• Cognitive Processing Depth: Visual search paradigms combined with fMRI (Jagiellowicz et al., 2011) demonstrate that high HSP individuals display enhanced activation in high-order visual processing areas (e.g., claustrum, left occipital-temporal cortex, angular gyrus) when discerning subtle differences between photographic scenes, underscoring that sensory sensitivity operates at stages of higher-order cortical processing.
• Autonomic and Endocrine Activity: Individuals with high SPS demonstrate unique patterns of autonomic nervous system (ANS) responsivity, characterized by distinct baseline parasympathetic tone (heart rate variability) and pronounced sympathetic and hypothalamic-pituitary-adrenal (HPA) axis reactivity when confronted with acute laboratory stressors.

Validity

The HSP Scale has undergone extensive empirical evaluation to establish its construct, convergent, discriminant, and predictive validity across diverse clinical, educational, and cross-cultural cohorts.

Construct and Convergent Validity

Construct validity was initially established by Aron and Aron (1997) through extensive convergent analyses comparing the HSP Scale with existing personality indices. The scale correlates moderately to strongly with related temperamental and trait constructs:

• Five-Factor Model (FFM): The HSP Scale total score consistently correlates positively with Neuroticism ($r = .35$ to $.55$) and Openness to Experience ($r = .20$ to $.40$). Crucially, subscale decomposition clarifies these correlations: Ease of Excitation and Low Sensory Threshold drive the association with Neuroticism (specifically facets of vulnerability and anxiety), whereas Aesthetic Sensitivity drives the correlation with Openness to Experience (specifically artistic, aesthetic, and emotional facets). The HSP Scale typically shows small, negative-to-negligible associations with Extraversion ($r = -.10$ to $-.25$), confirming that sensitivity is distinct from introversion; approximately 30% of high-scoring individuals identify as socially extraverted.
• Gray’s Reinforcement Sensitivity Theory: High HSP scores correlate positively with Gray’s Behavioral Inhibition System (BIS), which regulates avoidance of punishment and novel threat scanning, while showing weak or non-significant correlations with the Behavioral Activation System (BAS).
• Hartmann’s Thin Boundaries: The scale shares substantial variance with Hartmann’s Concept of Boundaries in the Mind, specifically correlating with “thin boundaries” ($r > .50$), reflecting permeable emotional and perceptual filters.

Discriminant Validity

A crucial psychometric challenge in sensitivity research is confirming that the HSP Scale does not merely measure clinical negative affectivity, neuroticism, or introversion under an alternative label. Discriminant validity has been robustly demonstrated through several lines of evidence:

• Independence from Pathological Neuroticism: Multiple regression and structural equation modeling (SEM) investigations have established that when Neuroticism and Negative Affectivity are statistically controlled, the HSP Scale (and particularly the AES and LST subscales) continues to predict unique variance in cognitive task performance, sensory awareness, physiological reactivity, and artistic engagement.
• Dissociation from Autism Spectrum Traits: Research comparing individuals with high SPS and individuals with Autism Spectrum Disorder (ASD) indicates that while both groups report sensory discomfort (elevated LST), individuals scoring high on the HSP Scale demonstrate preserved or enhanced socio-emotional empathy, theory of mind, and social communication skills, which are characteristically diminished or atypical in ASD cohorts.

Predictive and Criterion Validity

The HSP Scale reliably predicts subjective and objective behavioral outcomes under laboratory and naturalistic settings:

• Laboratory Performance and Overarousal: Consistent with Yerkes-Dodson arousal dynamics, high HSP scorers outperform low scorers on subtle sensory discrimination tasks under low-stress conditions, but their performance deteriorates significantly when observed or subjected to severe time pressures (confirming Item 26 validity).
• Vantage Sensitivity Outcomes: Longitudinal intervention studies (e.g., Pluess & Boniwell, 2015) demonstrate that high HSP Scale scores predict disproportionate psychological benefit (e.g., marked reductions in depression and anxiety) following school-based resilience interventions, whereas low-sensitivity peers show negligible change, establishing the scale’s utility as a predictive moderator of therapeutic efficacy.

Reliability

The reliability of the HSP Scale has been documented across dozens of independent psychometric evaluations across the globe, confirming stable measurement across diverse languages, age brackets, and cultural contexts.

Internal Consistency

In their seminal validation studies across seven distinct samples, Aron and Aron (1997) reported total scale internal consistency coefficients (Cronbach’s alpha) ranging from $\alpha = .85$ to $.87$. Subsequent replications using non-clinical adult, university, and community samples have confirmed these findings, typically observing alphas between $.85$ and $.89$ for the 27-item composite. When examined at the subscale level (following the tri-factor model of Smolewska et al., 2006):

• Ease of Excitation (EOE, 12 items): Cronbach’s alpha values typically span $.78$ to $.84$.
• Low Sensory Threshold (LST, 7 items): Cronbach’s alpha values range from $.72$ to $.80$.
• Aesthetic Sensitivity (AES, 8 items): Cronbach’s alpha values range from $.68$ to $.78$.

Recent studies reporting composite reliability ($
ho_c$) and McDonald’s \omega total ($omega_t$) similarly demonstrate values exceeding$.86$, indicating that the scale’s items collectively tap into a cohesive macro-construct of environmental sensitivity with minimal measurement error.

Test-Retest Reliability

Temporal stability assessments indicate that Sensory Processing Sensitivity represents an enduring temperamental trait rather than a transient affective state. Initial stability tests over periods spanning several weeks yielded test-retest correlation coefficients of $r = .75$ to $.85$. Long-term longitudinal follow-ups over multi-year intervals continue to demonstrate strong stability coefficients ($r > .70$), consistent with the stability profiles of foundational Big Five personality traits.

Cross-Cultural Invariance

The psychometric integrity of the HSP Scale has been substantiated through translated and culturally adapted instruments worldwide, including German, Italian, Spanish, Dutch, Japanese, Turkish, and Polish cohorts. Multi-group confirmatory factor analyses (MGCFA) have widely confirmed metric and scalar measurement invariance across biological sexes and partial scalar invariance across linguistic groups, establishing that the 27 items capture the underlying trait with structural fidelity across diverse populations.

Factor Analysis

The structural dimensionality of the Highly Sensitive Person Scale has generated considerable empirical dialogue, leading to significant advances in quantitative modeling of the trait.

Initial Unidimensional Solution

In their original 1997 validation, Aron and Aron performed an exploratory factor analysis (EFA) on a large undergraduate and community dataset. Principal components and common factor analyses with scree test evaluations led them to extract a single general factor accounting for the primary variance, which they interpreted as a unidimensional construct of Sensory Processing Sensitivity. The authors acknowledged that minor subsidiary factors existed (such as aesthetic enjoyment or physical sensitivity), but argued that a unitary aggregate score provided the most parsimonious representation for general empirical research.

The Tri-Factor Paradigm: Smolewska, McCabe, and Woody (2006)

Subsequent psychometric researchers raised concerns regarding item heterogeneity within the 27-item instrument. Smolewska, McCabe, and Woody (2006) conducted a principal components analysis with varimax rotation on data from 851 participants, revealing that a three-factor solution provided a superior conceptual and empirical fit. Confirmatory Factor Analysis (CFA) cross-validated this three-factor structure:

• Factor 1: Ease of Excitation (EOE) (Items 13, 14, 16, 17, 19, 21, 23, 26, etc.): Captures mental overload, disorganization, and negative emotional reactivity under task pressure or environmental complexity (factor loadings ranging from $.45$ to $.68$).
• Factor 2: Low Sensory Threshold (LST) (Items 1, 7, 9, 11, 25, etc.): Represents aversion and physiological discomfort to intense, noxious, or invasive physical sensory stimuli (factor loadings ranging from $.42$ to $.74$).
• Factor 3: Aesthetic Sensitivity (AES) (Items 2, 8, 10, 15, 22, etc.): Indexes the positive cognitive-affective processing of artistic, musical, olfactory, and nuanced environmental qualities (factor loadings ranging from $.40$ to $.71$).

Bifactor and Hierarchical Structural Models

To reconcile the dispute between a single general sensitivity trait and distinct sub-dimensions, contemporary structural investigations utilize bifactor modeling and hierarchical higher-order CFA (e.g., Lionetti et al., 2018). In these models, all 27 items load simultaneously onto a general Sensory Processing Sensitivity factor, while subsets of items load onto their specific orthogonal group factors (EOE, LST, and AES). Model fit indices across large samples consistently support the bifactor or higher-order framework over a strictly unidimensional model:

• Comparative Fit Index (CFI) $ge .92$
• Tucker-Lewis Index (TLI) $ge .90$
• Root Mean Square Error of Approximation (RMSEA) $le .055$ (90% CI [.050, .060])
• Standardized Root Mean Square Residual (SRMR) $le .058$

These findings substantiate that researchers may legitimately utilize both a total composite score (representing overarching environmental sensitivity) and the individual subscale scores to assess nuanced behavioral outcomes.

Taxometric and Latent Class Analyses: Dandelions, Tulips, and Orchids

An enduring empirical question centered on whether SPS is a continuous dimensional trait or a categorical taxon (a discrete psychological type). Taxometric analyses conducted by Aron, Aron, and Jagiellowicz (2012) initially suggested a discrete taxon constituting the upper 15–20% of the distribution. However, sophisticated Latent Class Analyses (LCA) and Latent Profile Analyses (LPA) conducted by Lionetti et al. (2018) across several thousand individuals established that sensitivity is distributed into three distinct sensitivity groups across a continuous spectrum:

• Low Sensitivity (“Dandelions”): Approximately 30% of the population; resilient individuals who function well across most environments but register less subtle contextual information.
• Medium Sensitivity (“Tulips”): Approximately 40% of the population; reflecting an intermediate, normative level of sensory and environmental sensitivity.
• High Sensitivity (“Orchids”): Approximately 30% of the population; individuals possessing high SPS who flourish exceptionally under optimal conditions but wither severely under chronic adversity.

Instrument / Measurement Tool

• Test Type: Standardized self-report psychometric rating scale
• Target Population: Adults (aged 18 and older); adaptable for older adolescents (a dedicated child instrument, the Highly Sensitive Child [HSC] Scale, exists for pediatric populations)
• Item Count: 27 items
• Administration Format: Paper-and-pencil or secure computer-based digital questionnaire; individual or group administration
• Completion Time: Approximately 7 to 12 minutes
• Response Scale: 7-point Likert-type scale with numerical ratings from 1 to 7:
  • 1 = Not at all
  • 2 = [Unlabeled intermediate]
  • 3 = [Unlabeled intermediate]
  • 4 = Moderately
  • 5 = [Unlabeled intermediate]
  • 6 = [Unlabeled intermediate]
  • 7 = Extremely
• Reverse-Scored Items: None. All 27 items are keyed positively in the direction of higher sensitivity.
• Scoring Procedures:
  • Total Score Calculation: Compute the arithmetic mean of all 27 items (yielding a continuous score between 1.00 and 7.00), or alternatively sum the responses (yielding a total raw score range of 27 to 189). In academic psychometrics, the mean score ($1.00 – 7.00$) is preferred to preserve interpretability against the response anchors.
  • Subscale Score Calculation (Tri-factor Model):
    • Ease of Excitation (EOE): Mean of Items 13, 14, 16, 17, 19, 21, 23, 24, 26, etc.
    • Low Sensory Threshold (LST): Mean of Items 1, 4, 6, 7, 9, 11, 25, etc.
    • Aesthetic Sensitivity (AES): Mean of Items 2, 3, 5, 8, 10, 12, 15, 18, 20, 22, 27, etc. (Item allocation varies slightly depending on specific translated factor analytic models; researchers should apply validated national factor matrices).
  • Cutoff and Categorization Rules: Historically, popular clinical screening established that scoring in the upper range (e.g., answering 14 or more items at the extreme end, or achieving a total mean score above approximately 4.5 to 5.0) indicates high sensitivity. Psychometric investigations applying latent class cutoffs classify individuals into low (< 3.6), medium (3.6 – 4.6), and high (> 4.6) sensitivity tiers.

Permissions & Fee and Test Year

The Highly Sensitive Person Scale was originally published in 1997 in the Journal of Personality and Social Psychology by the American Psychological Association (APA). The instrument is copyrighted by Elaine N. Aron, Ph.D.

Licensing and Research Use Policies:

• Academic and Non-Commercial Scientific Research: The HSP Scale is made freely accessible for academic, educational, and empirical research purposes. Researchers may reproduce and administer the scale in non-commercial psychological, medical, and educational studies without prior written permission or royalty fees, provided full bibliographic citation is given to Aron and Aron (1997).
• Clinical and Personal Screening: The scale is available for individual self-assessment and clinical screening through the author’s public academic educational portal (hsperson.com).
• Commercial, Corporate, and Digital Application Rights: Any utilization of the HSP Scale within commercial products, corporate coaching assessment batteries, proprietary mobile applications, or monetized digital platforms requires formal written licensing authorization from the copyright holder. Inquiries regarding commercial usage rights should be directed to the official estate of Elaine N. Aron via her designated academic communications channels.

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
• Acevedo, B., Jagiellowicz, J., Aron, E., Marhenke, R., & Aron, A. (2018). Sensory processing sensitivity and childhood environment predict brain responses to faces. Frontiers in Psychology, 9, 1415. https://doi.org/10.3389/fpsyg.2018.01415
• 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
• 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
• 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
• Evans, D. E., & Rothbart, M. K. (2008). Temperamental sensitivity: Two constructs or one? Personality and Individual Differences, 44(1), 108–118. https://doi.org/10.1016/j.paid.2007.07.016
• Jagiellowicz, J., Aron, A., Aron, E. N., Wang, T., Perez, V. W., & Shen, X. (2011). The sensory processing sensitivity trait is associated with greater visual cortex activation during visual search. Social Cognitive and Affective Neuroscience, 6(1), 38–47. https://doi.org/10.1093/scan/nsq017
• 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. https://doi.org/10.1038/s41398-017-0061-8
• Pluess, M. (2015). Individual differences in environmental sensitivity. Child Development Perspectives, 9(3), 138–143. https://doi.org/10.1111/cdep.12120
• 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. https://doi.org/10.1016/j.paid.2015.03.011
• 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 their relation to the HEXACO model of personality. Personality and Individual Differences, 40(6), 1269–1279. https://doi.org/10.1016/j.paid.2005.09.022
• Wolf, M., van Doorn, G. S., & Leimar, O. (2008). Evolutionary emergence of responsive and unresponsive personalities. Proceedings of the National Academy of Sciences, 105(41), 15825–15830. https://doi.org/10.1073/pnas.0805473105

Items of the Scale