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Thomas Lynch Ph.D.


Social Signaling

The missing ingredient in the treatment of chronic depression.

Source: TomLynch/Shutterstock

When we feel part of a tribe—we feel safe.

Humans are are a hyper-cooperative species—more so than any other animal species. We engage in highly complex and coordinated group activities with non-kin and comply without resistance to requests from complete strangers. Rather than falling apart or running amuck when disaster strikes—research shows that most humans are calm, orderly, and work together to help others. During times of extreme crisis—we forget about our individual differences, backgrounds, and beliefs and unite together for a common cause (e.g., ask anyone closely involved in the 9/11 crisis in New York City the extent they were worried about whether the person they were helping was homeless or a millionaire, religious or atheist, black or white).

A core component of this evolutionary advantage involved the development of complex social-signaling capabilities that allowed for a quick and safe means to evaluate/resolve conflict and manage potential collaborations. Indeed, our social signalling capacities are more powerful than most individuals realize as they viscerally impact not only the person we are interacting with but our own physiology as well—most often at the pre-conscious level. Slow-motion film analysis has robustly revealed that we react to changes in body movement, posture, and facial expressions of others during interactions without ever knowing it. Indeed, we are constantly social-signaling when around others (e.g., via micro-expressions, body movements)—even when deliberately trying not to. For example, ‘silence’ can be just as powerful as ‘non-stop talking’.

Plus, for our very early ancestors living in harsh environments the cost of not detecting a ‘true’ disapproval signal was too high to ignore—since tribal banishment was essentially a death sentence from starvation or predation (see Lonely Apes Die). As a consequence, we are constantly scanning the facial expressions and vocalizations of other people for signs of disapproval and are biologically predisposed to construe the intentions of others as disapproving—especially when social-signals are ambiguous. This means we are essentially a socially-anxious species. Blank expressions, furrowed brows, or slight frowns are often interpreted as disapproving—regardless of the actual intentions of the sender (e.g., some people frown or furrow their brow when intensely listening). Moreover, being rejected by a tribe hurts—research shows that social ostracism triggers the same areas of the brain that are triggered when we experience physical pain (Eisenberger & Lieberman, 2004). Thus, we fear the pain of social exclusion and our emotional well-being is highly dependent on the extent we feel part of a tribe and socially connected.

Interpersonal factors are known to be among the strongest predictors of persistent depression, even remaining robust after controlling for other important clinical variables (e.g., Lara, Leader & Klein, 1997). Unsurprisingly, given these scientific findings several systems of psychotherapy have been constructed to specifically impact these variables in depressed patients. However, none of these interpersonal-focused psychotherapy systems have specifically emphasized the targeting of our complex social signalling capabilities. Depressed patients are more likely to exhibit flat or disingenuous facial expressions, use monotonic or expressionless voice tones, speak more slowly, or pause more often during conversations relative to non-depressed individuals. Plus, robust research shows that context-inappropriate suppression of emotional expression or incongruent expression of emotion (i.e., what is expressed outwardly does not match inner experience) makes it more likely for others to perceive the inhibited/incongruent person as untrustworthy or inauthentic thereby reducing social connectedness and exacerbating psychological distress (e.g., Mauss et al., 2011).

Because of the importance of interpersonal variables in general, in maintaining depression and social signalling factors in particular, psychotherapy for chronic depression would be optimized with the inclusion of an emphasis on the latter as new means for potentiating change. Teaching depressed patients to pay attention to their social signalling style (rather than solely on what they feel or think inside) combined with social signalling skills training could be a powerful means for enhancing social connectedness and reducing the emotional loneliness and social isolation that characterizes chronic depression.

Indeed, my research team and I have developed a system of psychotherapy, Radically Open Dialectical Behavior Therapy (RO-DBT), with such an emphasis and found that it positively impacts difficult to treat depressions. RO-DBT is informed by a ‘collectivist’ rather than ‘individualistic’ model of emotion and emotional health—positing that ‘individual’ well-being is inseparable from the feelings and responses of the larger group or community. Thus, when it comes to long-term mental health and well-being—what a person feels or thinks inside or privately is considered less important in RO-DBT—whereas, how a person communicates or social-signals their inner or private experience to other members of their tribe and the impact it has on social-connectedness.

Feeling happy is great—but when you are lonely—it’s hard to feel happy no matter how much you might try to accept, reappraise, or change your circumstances, keep busy, exercise, practice yoga, or distract yourself. In the long run, we are tribal beings—and we yearn to share our lives with other members of our species. It was what we were born to do.

For more information, check out a comprehensive and up-to-date list of research on RO DBT.


Eisenberger, N. I., & Lieberman, M. D. (2004). Why rejection hurts: a common neural alarm system for physical and social pain. Trends in cognitive sciences, 8(7), 294-300.

Lara, M. E., Leader, J., & Klein, D. N. (1997). The association between social support and course of depression: is it confounded with personality?. Journal of Abnormal Psychology, 106(3), 478.

Mauss, I. B., Shallcross, A. J., Troy, A. S., John, O. P., Ferrer, E., Wilhelm, F. H., & Gross, J. J. (2011). Don't hide your happiness! Positive emotion dissociation, social connectedness, and psychological functioning. Journal of personality and social psychology, 100(4), 738.


About the Author

Thomas Lynch, Ph.D., is a professor and the Director of the Emotion and Personality Bio-behavioural Lab at the University of Southampton in the United Kingdom.