How do people navigate their social world to ensure that their belonging needs are met?
How do our prior interpersonal experiences influence our new relationships?
How do people balance their needs for closeness, or “communion,” with their (sometimes) competing needs for individuation, or “agency” (and vice versa)?

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It is well-known that the quantity and quality of our close relationships can have profound consequences for psychological and physical health. In contrast to many other species, human beings possess an extensive repertoire of skills that facilitate social connection (e.g., the ability to understand the emotions and intentions of others, to show compassion and empathy, and to help, care for, share, and cooperate with others). Notwithstanding these endowments, forming and maintaining close relationships is not always easy. At the McGill Lab of Affiliation and Prosociality, we are interested in understanding the factors that facilitate (or hinder) our ability to engage in the prosocial, communal behaviours that enable the development of trust and shared experience—without which closeness cannot be maintained over the long haul. Our research is grounded in empirical social psychology but also draws upon methods from neuroscience (e.g., pharmacological challenge, fMRI, genetics) to better understand the biological mechanisms involved. To this end, a major focus of our research is aimed at understanding the role of the oxytocin and opioid systems in human affiliation. 

Probing the mechanisms underlying the “prosocial” effects of oxytocin

Although oxytocin is popularly regarded as the "hormone of love", numerous studies have shown that there are important individual difference and situational moderators of the social effects of oxytocin in humans (Bartz, Zaki, Bolger, & Ochsner, 2011Bartz, 2016). These findings challenge simplistic notions about oxytocin function. In one line of research, we are exploring the underlying mechanisms by which oxytocin modulates prosocial cognition and behaviour in humans in order to (1) understand how oxytocin modulates prosociality and (2) predict when, and for whom, oxytocin manipulations would be expected to improve, leave unaltered, or even worsen social cognition and prosocial behavior.

Oxytocin and the self in relation to other

Biological correlates of intrapersonal stability and variability

Several studies suggest that polymorphisms of the oxytocin receptor gene (OXTR) are associated with indices of social sensitivity. Most of this research, however, has utilized self-report measures of traits (e.g., empathy) or task-based measures; very few researchers have attempted to study social cognition and behavior as it unfolds in real-life interpersonal interactions. In collaboration with Drs. Gentiana Sadikaj, Debbie Moskowitz, and David Zuroff at McGill, we are using event-contingent recording methodology to investigate the role of the OXTR gene (and other candidate genes) in interpersonal cognition, affect and behavior in everyday life. This methodology provides not only more reliable, and ecologically-valid, measures of social behavior, cognition, and affect but also an opportunity to examine variability in these indices due to specific features of the social situation and/or relationship. 

Attachment and altered endogenous oxytocin

Individual differences in attachment anxiety (a preoccupation with closeness and fear about abandonment), and avoidance (a desire to avoid intimacy and dependence) appear to be potent moderators of the social effects of oxytocin in humans. In fact, there is some evidence, both from research in animals and humans, to suggest that early caregiving experiences can disrupt the oxytocin system. Taken together, this points to the intriguing possibility that individual differences in attachment may be associated with underlying differences in the endogenous oxytocin system (which then impacts the effects of exogenous oxytocin administration). In collaboration with Drs. Phyllis Zelkowitz and Ian Gold, we are investigating whether individual differences in endogenous (plasma) oxytocin is associated with both explicit and implicit attachment in a sample of new mothers.

The opioid system and social motivation

In addition to the oxytocin system, the opioid system has also been hypothesized to play a key role in the initiation and maintenance of social bonds (e.g., Panksepp et al, 1980). This system regulates the experience of pleasure/reward and response to pain. According to the brain opioid theory of social attachment/motivation (Machin & Dunbar, 2011), endogenous opioids are responsible for the pleasure we feel when socially connected and, conversely, the pain we feel when socially disconnected, which then prompts socially motivated behavior to restore well-being. Although little research has been conducted to date in humans, data from non-human primates and other mammals support the opioid theory of social motivation. We are using the drug naltrexone (an opioid receptor antagonist) to investigate the effects of the opioid system on social motivation in humans.

Empathy under stress

The effects of oxytocin are often dependent on person-level factors (Bartz, 2016). For example, oxytocin appears to be especially beneficial (socially) for some individuals (e.g., those who are avoidantly attached, or those endorsing traits of autism; Bartz et al., PsychScience 2010), but unhelpful (socially) to others (e.g., anxiously attached; Bartz et al., PNAS, 2010, or those with borderline personality disorder; Bartz et al., SCAN , 2011).  One hypothesis we are exploring is that oxytocin modulates the self-in-relation-to-other, or agency-communion, balance. Specifically, increasing a communal, other-orientation (via oxytocin administration) should be especially helpful for those who are excessively focused on the self to the exclusion of others (low in communion). By contrast, increasing an other-orientation could be unhelpful, and perhaps harmful, for those who are already overly other-focused but have no sense of self (low agency), because it may further diminish the priority of the self. In this line of research, we are investigating the effects of oxytocin on agency and communion, and how this self-other balance affects empathy.

Empathy is a multi-faceted construct that involves (i) affect sharing/emotion contagion, (ii) cognitive empathy, or the ability to accurately infer the feelings and intentions of others, and (iii) prosocial helping to alleviate the other’s distress. One factor that has recently been shown to influence empathy is stress; however, findings are inconsistent. For example, stress appears to impair empathy in both mice and humans, at least at the emotion contagion level (Martin et al, 2015, Curr Biol). But, other studies indicate that stress can enhance empathy (e.g., Buchanan & Preston, 2014). To further complicate this question, sex/gender can moderate the physiological and psychological stress responses in humans, with men typically being more physiologically reactive to stress than women. In a series of studies, we are investigating the effects of psychosocial stress (inducted by the Trier Social Stress Test; TSST) on the various components of empathy.