Physiological Responses to Social and Nonsocial Stimuli in Neurotypical Adults With High and Low Levels of Autistic Traits: Implications for Understanding Nonsocial Drive in Autism Spectrum Disorders

Abstract

Researchers have suggested that the two primary cognitive features of autism spectrum disorder (ASD), a drive toward nonsocial processing and a reduced drive toward social processing, may be unrelated to each other in the neurotypical (NT) population and may therefore require separate explanations. Drive toward types of processing may be related to physiological arousal to categories of stimuli, such as social (e.g., faces) or nonsocial (e.g., trains). This study investigated how autistic traits in an NT population might relate to differences in physiological responses to nonsocial compared with social stimuli. NT participants were recruited to examine these differences in those with high vs. low degrees of ASD traits. Forty-six participants (21 male, 25 female) completed the Autism Spectrum Quotient (AQ) to measure ASD traits before viewing a series of 24 images while skin conductance response (SCR) was recorded. Images included six nonsocial, six social, six face-like cartoons, and six nonsocial (relating to participants' personal interests). Analysis revealed that those with a higher AQ had significantly greater SCR arousal to nonsocial stimuli than those with a low AQ, and the higher the AQ, the greater the difference between SCR arousal to nonsocial and social stimuli. This is the first study to identify the relationship between AQ and physiological response to nonsocial stimuli, and a relationship between physiological response to both social and nonsocial stimuli, suggesting that physiological response may underlie the atypical drive toward nonsocial processing seen in ASD, and that at the physiological level at least the social and nonsocial in ASD may be related to one another.

Autonomic Reactivity to Arousing Stimuli with Social and Non-social Relevance in Alexithymia

“…The low autonomic reactivity observed in CA group to social relevant information was not linked to values of social phobia, anxiety, and depression. Previous studies on social relevance showed significant differences on the reactivity at central (Proverbio et al, 2009; Groen et al, 2013) and peripheral levels (Althaus et al, 2014; Singleton et al, 2014). Regarding peripheral level and particularly skin conductance measures, it has been reported that healthy participants showed higher SCRs to stimulus with than without social relevance, while subjects with some social disorders (e.g., autism) showed the opposite pattern (Singleton et al, 2014).…”

“…Another important issue is related to the distinction human/non-human vs. social/non-social. Though our approach was similar to that of other authors (Proverbio et al, 2009; Groen et al, 2013; Singleton et al, 2014), it could be of interest to disentangle in future designs two aspects contained in what was called ‘social’ factor, by using for example pictures showing one vs. several individuals belonging to human vs. non-human species. In addition, considering that strategies of each group to perceive and analyze social vs. non-social emotional stimuli need to be better understood, we are running experiments integrating eye saccadic movements during the projection of each picture to explore this issue.…”

“…In the same way, we found an inversion between NA and CA participants. We have to remember that if the SCR has been widely related with the activation originating in emotions (Bradley and Lang, 2000; Critchley, 2002; Sequeira et al, 2009), it has also been associated with attention and motivational significance of the stimulus (Bradley, 2009; Singleton et al, 2014). In this line, the SCR is considered as an orienting response, in accordance with the role of the sympathetic system in arousing and engaging behavioral and physiological reactions to salient stimulation (Bradley, 2009; Sequeira et al, 2009; Boucsein, 2012).…”

“…Previous studies reported significant effects of the social content (human vs. non-human) of emotional stimuli on the reactivity at central level, through evoked potential analysis (Proverbio et al, 2009; Groen et al, 2013) and at peripheral level, through autonomic measures (Althaus et al, 2014; Singleton et al, 2014). This social effect has been related to an automatic attentional affective processing, which facilitates the empathy (Proverbio et al, 2009; Groen et al, 2013) or social abilities (Althaus et al, 2014; Singleton et al, 2014). In this line, Singleton et al (2014), found higher values of SCRs for social relevant stimulus than for those without social relevance, in healthy participants scoring high in autistic symptoms scale.…”

“…This social effect has been related to an automatic attentional affective processing, which facilitates the empathy (Proverbio et al, 2009; Groen et al, 2013) or social abilities (Althaus et al, 2014; Singleton et al, 2014). In this line, Singleton et al (2014), found higher values of SCRs for social relevant stimulus than for those without social relevance, in healthy participants scoring high in autistic symptoms scale. Therefore, the distinct profiles of alexithymic dimensions characterized by neuroanatomical differences in the brain limbic structures (Van der Velde et al, 2014; Goerlich-Dobre et al, 2015a) could present different automatic attentional affective processing to social and no social stimulus, which are relevant to empathy and social processes (Proverbio et al, 2009; Bogdanov et al, 2013; Groen et al, 2013).…”