تعدیل ارتباط بین تجارب دوران کودکی و رضایت از زندگی بزرگسالان با حساسیت حسی پردازش

There are few studies testing the differential susceptibility hypothesis (DSH: hypothesizing that some individuals are more responsive to both positive and negative experiences) with adult personality traits. The current study examined the DSH by investigating the moderating effect of sensory-processing sensitivity (SPS) on childhood experiences and life satisfaction. A total of 185 adults completed measures of SPS, positive/negative childhood experiences and life satisfaction. SPS did moderate the association between childhood experiences and life satisfaction. Simple slopes analysis compared those reporting high and low SPS (+/− 1 SD) and revealed that the difference was observed only for those who reported negative childhood experiences; with the high SPS group reporting lower life satisfaction. There was no difference observed in those reporting positive childhood experiences, which supported a diathesis-stress model rather than the DSH.

The quest to identify the precursors and predictors of adult mental wellbeing is an important one. In the most general terms, life events – positive and negative – as well as inherited factors are likely to play an influential role in determining and modifying mental wellbeing throughout the lifespan. It is no surprise then that gene-by-environment (G × E) research designs are commonly used to investigate research questions in this field (Bakermans-Kranenburg & van IJzendoorn, 2014). While genes and life events can jointly, as well as independently affect mental wellbeing, a growing body of research is emerging that shows that these effects may also be observed in trait-by-environment (T × E) designs (Aron, Aron, & Jagiellowicz, 2012). In other words, individual differences in personality traits can influence the impact of different life events on a person's wellbeing. Evidence from evolutionary biology suggests that a fundamental personality trait that occurs across nonhuman and human species involves individual differences in responsiveness, reactivity, flexibility and sensitivity to the environment (Wolf, Van Doorn, & Weissing, 2008). There is a growing consensus among personality researchers that “a fundamental factor structuring [animal] personality differences is the degree to which individual behaviour is guided by environmental stimuli” (p. 15,835). Aron and colleagues have conceptualized this trait in humans as relating to sensory-processing sensitivity (SPS: Aron and Aron, 1997 and Aron et al., 2012), which they see as being a reflection of one of two strategies that has evolved in many species: a strategy of either responding more to the environment or responding less. High SPS has been compared to the personality trait introversion ( Eysenck, 1981) and the behavioural inhibition system ( Gray, 1981). The responsive strategy, or high SPS, is characterized by a tendency to “pause to check” in novel situations, greater sensitivity to subtle stimuli, and the engagement of deeper cognitive processing strategies for employing coping actions, all of which is driven by heightened emotional reactivity, both positive and negative ( Aron & Aron, 1997; 2012). Thus, some individuals are simply more responsive and reactive to stimulation from the environment than others. This assumption relates to the differential susceptibility hypothesis (DSH: Belsky, 1997), which states that there are some inherent characteristics which make individuals more responsive to their environment, be that positive or negative. In combination with negative stressful experiences, individuals who possess these characteristics are likely to become overwhelmed and display poor outcomes, whereas these same individuals are likely to flourish under positive and enriching experiences. While the non-responsive characteristics may be beneficial to buffer against the effects of negative environmental stress — the responsive characteristics may provide an advantage in positive environments. Belsky and Pleuss (2009) argue that many of these responsive characteristics have been misrepresented in the literature as risk alleles, or diathesis-stress models ( Zuckerman, 1999) – predisposing individuals to mental disorders – because previous research has failed to assess the interaction between individual differences and positive environments, which is a direction for future research. If certain characteristics are able to show both a disadvantage in combination with negative experiences and an advantage in combination with positive experiences, then they should be considered a plasticity factor — rather than a risk. There has been some evidence to suggest that SPS is a plasticity factor. Using their measure of SPS – the Highly Sensitive Person Scale (HSPS) (Aron & Aron, 1997) – Aron, Aron, and Davies (2005) were able to show that high SPS university students reported a greater increase in negative affectivity after a difficult scholastic test, whereas they also showed a greater reduction in negative affectivity after an easy test — compared to their low SPS colleagues. In another study, high SPS children – as measured by the HSPS for children (Pleuss & Boniwell, 2015) – showed advantageous outcomes in terms of reduced depression symptoms, while their low SPS counterparts showed no improvement (Pleuss & Boniwell, 2015). This finding was stable at 6 and 12 month follow-up assessments. The authors suggested that a possible reason for this advantage was due to the nature of high SPS, which is characterized by a sensitive nervous system and the processing of information more deeply, which may have led to greater internalization of the intervention. This is supported by studies which find that SPS is related to cognitive advantages, such as greater detection of subtle changes in visual scenes (Jagiellowicz et al., 2011) and faster reaction times and fewer errors in a visual detection task (Gerstenberg, 2012). Despite this evidence suggesting that SPS may be a plasticity factor, a number of studies have documented negative associations with SPS (Ahadi and Basharpoor, 2010 and Liss et al., 2005). In a cross-sectional study assessing parental bonding an interaction was found between parental care and SPS; as high SPS individuals reported more depression symptoms than low SPS individuals when care was low, but the two groups did not differ in depression symptoms when care was high, supporting a diathesis-stress model (Liss et al., 2005). This finding suggests that SPS is a risk factor, especially since a correlation was found between SPS and depression (r = .22, p < .001). However, the authors failed to assess any positive outcomes that could have differentiated high and low SPS individuals under positive experiences. This is a major flaw in the literature, which has not provided a balanced view of positive and negative outcomes and biases certain traits as being risk factors rather than potential plasticity factors ( Belsky and Pleuss, 2009 and Manuck, 2010). Another potential reason that SPS has been associated with negative outcomes is that the HSPS may be primarily measuring negative reactivity in response to overstimulation (Aron et al., 2012). The 27-item scale is replete with items concerning being “overwhelmed… bothered… made uncomfortable… annoyed” by different types of stimulation. A psychometric evaluation of the scale has found a clear three-factor structure (Smolewska, McCabe, & Woody, 2006) consisting of i) Ease of Excitation (EOE: e.g. “do you find it unpleasant to have a lot going on at once?”), ii) Low Sensory Threshold (LST: e.g. “are you made uncomfortable by loud noises?”), and iii) Aesthetic Sensitivity (AES: e.g. “do you seem to be aware of the subtleties in your environment?”). The former two were found to correlate highly with Neuroticism, while the latter was found to correlate most with Openness to Experience (NEO-FFI; Costa and MacCrae, 1992), which is the personality dimension most associated with aesthetic sensitivity, attentiveness to inner feelings and intellectual curiosity. Despite finding evidence for a three-factor structure of the HSPS, it was concluded that high intercorrelations between factors and the overall scale suggested that it was an adequate measure of the higher-order trait of SPS ( Smolewska et al., 2006). As yet, there has not been a research study to investigate possible plasticity effects for these factors individually, despite different results being shown between the factors, such as the correlations with different personality traits ( Smolewska et al., 2006) and performance on a cognitive task ( Gerstenberg, 2012). The aims of the current study were threefold — i) to assess a continuous predictor and outcome variable that would be able to differentiate positive and negative extremes, which would correct for previous studies that failed to do so ( Belsky and Pleuss, 2009 and Liss et al., 2005), ii) to assess possible plasticity effects for the three factors within SPS ( Smolewska et al., 2006), and iii) to use a heterogeneous adult community sample ( Aron et al., 2005). In this study, we investigated whether SPS would moderate the association between childhood experiences (positive & negative) and current life satisfaction. We hypothesized that high SPS individuals would show both the best and worst outcomes relative to their childhood experiences. We had no clear hypotheses for whether the three factors would interact differently with childhood experiences.