Sofie Weyn

Adolescence is a period of heightened developmental plasticity across biological, socio-emotional, and behavioral domains (Sawyer et al., 2018; Steinberg & Morris, 2001). Environmental influences d...

Environmental sensitivity, defined as the capacity to perceive and process information from both supportive and adverse environmental experiences, plays an important role in socio-emotional and behavioral development. However, existing research has predominantly focused on childhood, leaving a gap in our understanding of environmental sensitivity during adolescence. To bridge this gap, we conducted three studies using self-report data from 2,375 Japanese adolescents aged 10–14 years and their mothers. First, we aimed to provide a comprehensive description of adolescent sensory processing sensitivity (referred to as trait sensitivity) by applying the 21-item Highly Sensitive Child scale to Japanese adolescents (Studies 1 and 2). Second, using three-wave longitudinal data, we examined how trait sensitivity interacts with various environmental contexts (i.e., negative/positive parenting and peer relationships) to predict adolescents’ socio-emotional and behavioral development (Study 3). Results showed that adolescent trait sensitivity was characterized by a general factor reflecting sensitivity to a broad range of negative and positive stimuli, as well as two specific domains: Ease of Excitation–Low Sensory Threshold and Aesthetic Sensitivity (i.e., bifactor model). Trait sensitivity was positively correlated with other temperament and personality traits, including negative emotionality, behavioral inhibition, neuroticism, and openness. Trait sensitivity and environmental factors independently predicted internalizing and externalizing problems, as well as prosocial behavior. Notably, trait sensitivity was a significant positive predictor of both internalizing problems and prosocial behavior. These findings suggest partial continuity in the structure and developmental functions of trait sensitivity from childhood to adolescence.

Individuals differ in how they perceive and process social and sensory information in their environment, a personality trait known as Sensory Processing Sensitivity (SPS). Approximately 30% of the general population scores high on this trait making them more responsive to both negative and positive environmental influences than individuals lower in SPS. Overstimulation is one of the biggest challenges associated with SPS. Associations between SPS, triggers, and fluctuations of overstimulation in everyday life were examined using an experience sampling method study (during one week with 5 prompts a day) in 139 healthy adults. Results showed that overstimulation increased in the afternoon to early evening and in the presence of others. Furthermore, more sensitive individuals reported higher levels of overstimulation when auditory and visual stimuli were rated as unpleasant, when fatigued, or in a negative mood. Yet, more sensitive individuals reported lower levels of overstimulation with momentary pleasant auditory and visual stimuli, when not fatigued, and in a positive mood at the current moment. Everyone, but particularly individuals high in SPS, may benefit from interventions preventing fatigue, promoting positive mood and the pleasantness of sensory stimuli in their daily environments to reduce feelings of overstimulation.

Supportive parenting experiences link to secure attachment development, and secure attachment in turn links to children’s emotional well-being. However, little is known whether child-factors, like their environmental sensitivity, moderate these associations for better or for worse. We used longitudinal data (three data waves spanning two years) from 614 children (Wave 1: M _age = 10.28; SD _age = 0.58; 44% boys). At all waves, attachment was operationalized as children’s knowledge of the Secure Base Script with a coded narrative task. Children filled out questionnaires on supportive parenting, their environmental sensitivity and their depressive symptoms. Parents filled out questionnaires on children’s internalizing problems. Results: environmental sensitivity moderated the link between supportive parenting and attachment. More sensitive children that perceived their parents as less supportive less likely developed SBS knowledge. Further, environmental sensitivity moderated the link between SBS knowledge and the development of internalizing problems. More sensitive children with less SBS knowledge developed more internalizing problems. The findings support the importance of accounting for environmental sensitivity in attachment research.

Approximately 30% of the general population scores high on the personality trait Sensory Processing Sensitivity (SPS). Overstimulation is one of the most reported challenges associated with SPS. Associations between SPS, triggers, and fluctuations of overstimulation in everyday life were examined using an experience sampling method study in 139 healthy adults. Results showed that overstimulation peaked in the early evening and in the presence of others. A cross-over effect depending on SPS levels was found. More sensitive individuals reported higher levels of overstimulation when auditory and visual stimuli were rated as unpleasant, when fatigued, or in a negative mood. Yet, more sensitive individuals reported lower levels of overstimulation with momentary pleasant auditory and visual stimuli, when not fatigued, and in a positive mood at the current moment. Everyone, but especially individuals high in SPS, might benefit from interventions preventing high levels of fatigue, increasing positive mood and the pleasantness of sensory stimuli in their daily life to reduce feelings of overstimulation.

This study investigated the psychometric properties of the Highly Sensitive Child-Rating System (HSC-RS), the existence of sensitivity groups, and the characterization of sensitivity at behavioral, genetic, and physiological levels in 541 preschoolers ( M ( SD ) _age = 3.56(0.27); 45%male; 87%Caucasian). Temperament, genetic, cortisol, and electroencephalography asymmetry data were collected in subsamples ( n = 94-476). Results showed a reliable observational measure of sensitivity. Confirmatory factor and latent class analysis supported a one-factor solution and three sensitivity groups, that are a low (23.3%), medium (54.2%), and a high (22.5%) sensitivity group. Hierarchical regression analyses showed moderate associations between HSC-RS and observed temperament traits (i.e., behavioral level). In addition, a small negative association between HSC-RS and a genome-wide association study polygenic risk score (GWAS PGS) for Attention Deficit Hyperactivity Disorder was found. No relations with candidate genes, other GWAS PGS phenotypes, and physiological measures were found. Implications of our findings and possible explanations for a lack of these associations are discussed.

Dit proefschrift biedt meer inzicht in de meting van individuele verschillen in omgevingssensitiviteit en in de karakterisering ervan over meerdere analyseniveaus, namelijk het fenotypische, fysiologische en genetische niveau. In het eerste deel evalueerden we de psychometrische eigenschappen van een zelfrapportagevragenlijst over leeftijd, geslacht, land en informanten en verbeterden we deze schaal (hsc-21). In het tweede deel karakteriseerden we individuele verschillen in omgevingssensitiviteit zoals gemeten met de hsc-21 schaal en een observatiemethode, op gedrags-, fysiologisch en genetisch niveau. Wij vonden zinvolle associaties met temperament, een genetische sensitiviteit en zelfgerapporteerde stress, maar niet met de biologische stressrespons. This doctoral thesis provides more insight into the measurement of individual differences in environmental sensitivity and its characterization across multiple levels of analysis, namely the phenotypic, physiological and genetic level. In the first part of the doctoral thesis, we evaluated and improved the psychometric properties of a self-report questionnaire measuring individual differences in environmental sensitivity across age, gender, country, and informants (HSC-21). In the second part, we characterized individual differences in environmental sensitivity as measured by the HSC-21 scale and an observational method, at the behavioral, physiological and genetic level. We found meaningful associations with temperament, a genetic sensitivity and self-reported stress, but not with the biological stress response.

Children differ in their sensitivity to positive and negative environmental influences, which can be measured with the Highly Sensitive Child (HSC) scale. The present study introduces the HSC-21, an adaptation of the original 12 item scale with new items and factor structure that are meant to be more informative than the original ones. The psychometric properties of the HSC-21 were investigated in 1,088 children across Belgium and the Netherlands, including child and mother reports. Results showed evidence for (a) bifactor model with a general sensitivity factor and two specific factors (i.e., Ease of Excitation–Low Sensory Threshold and Aesthetic Sensitivity); (b) (partial) measurement invariance across gender, developmental stage, country, and informants; (c) moderate child–mother agreement; (d) good reliability; (e) normally distributed item scores; and (f) meaningful associations with personality and temperament across both samples. No evidence was found for HSC-21 as a moderator in the relationship between parenting and problem behaviors.