Editing Sensory processing sensitivity (section)

==Attributes, characteristics and prevalence==
Boterberg ''et al.'' (2016) describe high SPS as a "temperamental or [[Trait theory|personality trait]] which is present in some individuals and reflects an increased sensitivity of the [[central nervous system]] and a deeper [[Cognition|cognitive processing]] of physical, social and emotional stimuli."<ref name=Boterberg2016/>

People with high SPS report having a heightened response to stimuli such as [[Pain stimulus|pain]], [[caffeine]], hunger, and loud noises.<ref name=Liss2008/> According to Boterberg ''et al.'', these individuals are "believed to be easily overstimulated by [[Stimulus (physiology)|external stimuli]] because they have a lower [[Perceptual learning|perceptual threshold]] and process stimuli cognitively deeper than most other people."<ref name=Boterberg2016/> This deeper processing may result in increased reaction time as more time is spent responding to cues in the environment, and might also contribute to cautious behavior and low risk-taking.<ref name=Boterberg2016/>

[[File:2015 Models of environmental sensitivity - based on M. Pluess.svg |thumb |right |upright=1.5| SPS involves responsiveness to both environmental adversity and positive environmental aspects, respectively modeled by the diathesis–stress model and the vantage sensitivity framework.<ref name=PluessIndivDiffEnvSens_2015/>]]
The HSP Scale, initially (1997) a questionnaire designed to measure SPS on a unidimensional scale, was subsequently decomposed into two,<ref name=EvansRothbartTwoConstructs2008/><ref name=TwoSubscales/> three,<ref name=ThreeSubscales/> or four<ref name=FourSubscales/> factors or sub-scales.<ref name=Boterberg2016/> Most components have been associated with traditionally accepted negative psychological outcomes<ref name=Boterberg2016/><ref name=Booth2015/> including high [[stress (biology)|stress]] levels, being easily overwhelmed, increased rates of [[clinical depression|depression]], [[anxiety]], and  [[Sleep disorder|sleep problems]], as well as [[autism|autistic]] traits;<ref name=Boterberg2016/> the [[diathesis–stress model]] focused on increased vulnerability to negative influences.<ref name=DiffSuscep2009/> However, the [[Differential susceptibility hypothesis|differential susceptibility theory]] (DST)<ref name=DiffSuscep2009/><ref name=BoyceReview2015/> and biological sensitivity to context theory (BSCT)<ref name=BoyceEllisBSCorchidDandelion2005/> and sensory processing sensitivity (SPS)<ref name=EllisDiffSuscEnvt2011/> suggest increased [[Neuroplasticity|plasticity]] in terms of responsiveness to both positive and negative influences; and the [[vantage sensitivity]] (VS) concept emphasizes increased responsiveness to positive experiences.<ref name=VantageSens2013/><ref name=ThibodeauEnvSens2016/> Researchers such as Smolewska ''et al.'' (2006) said positive outcomes were more common in individuals with high [[aesthetic]] sensitivity, who tend to experience heightened positive emotions in response to rewarding stimuli and more likely to score high on "openness" on the [[Big Five factors]] model.<ref name=PsychometricEval2006/>

Research in [[evolutionary biology]] provides evidence that the trait of SPS can be observed, under various terms, in over 100 nonhuman species,<ref name=Boterberg2016/><ref name=WolfEmergenceResponsive2008/> Aron writing that the SPS trait is meant to encompass what [[Personality psychology|personality psychologists]] have described under various other names.<ref name=RelatedConcepts/> Conversely, Aron has distinguished SPS from what she considers it is not, explicitly distinguishing<ref name=DistinguishingSPS/> high SPS from possibly similar-appearing traits or disorders (such as [[shyness]],<ref name=AdultShyness2005/><ref name=PsychologyToday20120202/> [[Sensation seeking|sensation-seeking]],<ref name=HSPinLove/> [[sensory processing disorder]],<ref name=AronReview2012/> and autism<ref name=JournalJung2006/>), and further, that SPS may be a basic variable that may underlie multiple other trait differences<ref name=AronAronJPSP1997/> (such as [[extraversion and introversion|introversion versus extraversion]]<ref name=DistinguishingSPS/>). Contrary to common misconception, according to Aron HSPs include both introverts and extroverts,<ref name=PsychologyToday20110721/> and  may be simultaneously high-sensation seeking and cautious.<ref name=HSPinLove/>

In humans and other species, responsive and unresponsive individuals coexist and consistently display different levels of responsiveness to environmental stimuli, the different levels of responsiveness having corresponding [[evolution]]ary costs and benefits.<ref name=WolfEmergenceResponsive2008/> This observation parallels Aron's assertion that high SPS is not a disorder, but rather a personality trait with attendant advantages and disadvantages.<ref name=JournalJung2006/><ref name=201804AcevedoHSBrainVsDisorders/> Accordingly, Aron cautions medical professionals against prescribing [[Psychoactive drug|psychoactive medications]] to "cure" the trait, which may or may not coexist with an actual disorder.<ref name=HSpersonBook_pp194-195/>

By 2015 the trait had been documented at various levels of study, including [[Personality psychology|temperament]] and [[Behaviorism|behavior psychology]], brain function and [[Sensitization|neuronal sensitization]], and [[genetics]].<ref name=BoyceReview2015/> For example, genetic studies provide evidence that higher levels of SPS are linked to the [[serotonin transporter]] [[5-HTTLPR]] short/short [[genotype]],<ref name=LichtSerotonin2011/> [[Polymorphism (biology)|polymorphisms]] in [[dopamine]] [[neurotransmitter]] genes,<ref name=ChenDopamine2011/> and the [[Alpha-2B adrenergic receptor|ADRA2b]] [[norepinephrine]]-related gene variant.<ref name=ToddEnhanceVivid2015/>

A 2015 longitudinal study based on army medical records of Swedish men showed a correlation between low [[resting heart rate]] and violence and criminality, with the authors theorising that lower sensitivity to stimulation resulted in increased likelihood of risk-taking and sensation-seeking behaviour – effectively a low sensitivity counterpart to SPS.<ref>[https://jamanetwork.com/journals/jamapsychiatry/fullarticle/2436277 A Longitudinal Study of Resting Heart Rate and Violent Criminality in More Than 700 000 Men]. 
Antti Latvala, Ralf Kuja-Halkola, Catarina Almqvist, et al. 
JAMA Psychiatry. 2015;72(10):971–978. doi:10.1001/jamapsychiatry.2015.1165</ref>

HSP Scale score patterns in adults were thought to be distributed as a [[wiktionary:dichotomous|dichotomous]] [[categorical variable]] with a break point between 10% and 35%,<ref name=AronReview2012/> with Aron choosing a cut-off of the highest-scoring 20% of individuals to define the HSP category.<ref name=Boterberg2016/> A 2019 review article stated that findings suggest people fall into three sensitivity groups along a [[normal distribution]] sensitivity continuum.<ref name=Greven_201903/>