The effects of social chemosignals on the psychophysiological correlates of motivational dysregulation in social anxiety and depression

Previous literature posited that human behavior is driven by the motivation to approach rewards and the motivation to avoid threats. The so-called approach and avoidance motivational systems are independent and separate, but they interact in orienting responses to emotional stimuli and in influencing ongoing affect (Lang et al., 1998). More recently, this model has been applied to the domain of social motivation (Gable, 2006). According to this model, approach social goals (e.g., “to make friends”) and avoidance social goals (e.g., “to not be lonely”) represent dispositional constructs that stimulate appetitive and aversive behaviour, respectively (Gable & Gosnell, 2013). Depression and social anxiety are mental disorders both characterized by impaired social functioning. Social anxiety is characterized by intense fear and avoidance of social situations (Hofmann & Bogels, 2006), and it has been associated with increased activity of the defensive motivational system (Davidson et al., 2000; Nusslock et al., 2015). Conversely, depressive disorders are characterized by anhedonia, apathy, and psychomotor retardation, which seem to be associated with hypoactivation of the appetitive motivational system (Henriques & Davidson, 1990; Stewart et al., 2010), resulting in a reduced propensity for approach-related action tendencies. Notably, humans transfer socially-relevant information (such as age, health status, and personality traits) and emotional states via body odors (also referred to as chemosignals) (Parma et al., 2017; Pause, 2012, 2017). Within the emotional states, individuals exposed to body odors report a partial reproduction of the affective, perceptual, and behavioral state of the sender, in a phenomenon called as “emotional contagion” (Semin, 2007). For example, anxiety chemosignals induce in the receivers an increase in withdrawal behaviors (measured by the startle reflex, Pause et al., 2009), a reduction in the perceptual acuity to happy facial expressions (Pause et al., 2004; Zernecke et al., 2011) and an augmented acuity to negative facial expressions (Zhou & Chen, 2009). On the other side, happiness body odors can induce in the receivers a happier facial expression than neutral body odors and a global processing style, which is typical under positive mood conditions (de Groot et al., 2015). However, despite the ability of body odors to convey emotional information, their role as a context in the processing of emotional stimuli is still widely unknown. Given the role of odors as powerful emotional stimuli and their role in affecting the subjective perceptual experiences and the psychophysiological processing of emotional stimuli, this project aims to investigate whether happiness and fear body odors could modulate subjective and psychophysiological processing of neutral facial expression in individuals with symptoms of depression and in individuals with symptoms of social anxiety.