Emotions are contagious. They are rapidly, frequently, and even at times automatically transmitted from one person to the next. Whether it be mind-boggling awe watching the supermoon display its lunar prowess or pangs of anger observing palpable racial injustice, one feature remains salient: we can and often do “catch” the emotions of others. The notion that emotions are contagious dates back as early as 1750s when Adam Smith documented the seamless way people tend to mimic the emotional expressions, postures, and even vocalizations of the people we interact with. In the late 1800s, Charles Darwin further emphasized that this highly contagious nature of emotions was fundamental to the survival of humans and nonhumans alike in transmitting vital information among group members. These prescient observations underscore the fact that emotion contagion is pervasive and universal and, hence, why it ought to be more widely known.
More recent scientific models of emotion contagion expound the features of, and mechanisms by which, we are affected by, and affecting, the emotions of others. Emotional contagion has been robustly supported in laboratory studies eliciting transient positive and negative emotion states among individual participants as well as efforts outside of the laboratory focused on longer-lasting mood states such as happiness among large social networks. Importantly, emotion contagion matters: it is in the service of critical processes such as empathy, social connection, and relationship maintenance between close partners.
When disrupted, faulty emotion contagion processes have been linked to affective disturbances. With the rapid proliferation of online social networks as a main forum for emotion expression, we know too that emotion contagion can occur without direct interaction between people or when nonverbal emotional cues in the face and body are altogether absent. Importantly, too, this type of contagion itself spreads across a variety of other psychological phenomenon that indirectly or directly involves emotions ranging from kindness, health-related eating behaviors, and even the darker side of human behaviors including violence and racism. Emotion contagion matters, for better and for worse.
Although well-documented emotion contagion warrants room to widen its own scientific scope. One uncharted domain my colleagues Nicholas Christakis, Jamil Zaki, Michael Norton, Ehsan Hoque and Anny Dow have been trailblazing is the unchartered realm of positive emotion contagion. Surprisingly, we know little about the temporal dynamics of our positive experiences, including those that both appear to connect us with others and should thereby propagate rapidly (such as joy or compassion) versus those that might socially isolate ourselves from others (such as hubristic pride). Given the vital role positive emotions play in our well-being and physical health, it is critical to better understand the features of how we transmit these pleasant states within and across social groups. Like waves, emotions cascade across time and geographical space. Yet their ability to cascade across psychological minds is unique and warrants wider recognition.