We participate in this interpersonal economy whenever a social interaction results in a transfer of feeling–which is virtually always. Such interpersonal judo has countless variations, but they all come down to our ability to change another person's mood, and they ours. When I make you frown, I evoke in you a touch of worry; when you make me smile, I feel happy. In this clandestine exchange, emotions pass from person to person, from outside to inside–hopefully for the best.
A downside of emotional contagion comes when we take on a toxic state simply by being around the wrong person at the wrong time. I was an unwitting victim of that security guard's fury. Like secondhand smoke, the leakage of emotions can make a bystander an innocent casualty of someone else's toxic state.
In moments like mine with that guard, as we confront someone's anger, our brain automatically scans to see if it signals some further danger. The resulting hypervigilance is driven largely by the amygdala, an almond-shaped area in the midbrain that triggers the fight, flight, or freeze response to danger. Of the entire range of feeling, fear most powerfully arouses the amygdala.
When it is driven by alarm, the amygdala's extensive circuitry commandeers key points throughout the brain, shepherding our thoughts, attention, and perception toward whatever has made us afraid. We instinctively become more attentive to the faces of the people around us, searching for smiles or frowns that give us a better sense of how to interpret signs of danger or that might signal someone's intentions.
This increased amygdala-driven vigilance heightens our alertness to emotional cues in other people. That intensified focus in turn more powerfully evokes their feelings in us, lubricating contagion. And so our moments of apprehension increase our susceptibility to another person's emotions.
More generally, the amygdala acts as a radar for the brain, calling attention to whatever might be new, puzzling, or important to learn more about. The amygdala operates the brain's early warning system, scanning everything that happens, ever vigilant for emotionally salient events–especially for potential threats. While the amygdala's role as a sentinel and trigger for distress is old news to neuroscience, its social role, as part of the brain's system for emotional contagion, has been revealed only recently.
THE LOW ROAD: CONTAGION CENTRAL
A man doctors call Patient X had suffered two strokes that destroyed the connections between his eyes and the rest of the brain's system for sight in the visual cortex. Though his eyes could take in signals, his brain could not decipher them, nor even register their arrival. Patient X was completely blind–or so it seemed.
On tests where Patient X was presented with various shapes like circles and squares, or photos of faces of men and women, he hadn't a clue what his eyes were gazing at. Yet when he was shown pictures of people with angry or happy faces, he suddenly was able to guess the emotions expressed, at a rate far better than chance. But how?