Sighs and shrugs are more powerful than they may seem.
Psychological research has clearly demonstrated that nonverbal cues from others can cause cognitive and emotional reactions in us. These cues can alter or control our own reactions and behavior—and often occur outside of
1. Pupil Dilation.
Research has shown that pupil dilation accompanies a sense of interest—we are interested in something and our pupils dilate to help us study it. Studies of physical attraction show that others with dilated pupils are viewed as more sexually attractive, presumably because we believe that the other person is interested in us. In ancient times, women would often dilate their pupils with belladonna to make themselves more attractive. This subtle cue definitely occurs outside our awareness.
2. Duchenne Smile.
The Duchenne smile is the term given to a genuine smile—a smile that occurs because someone is happy. A Duchenne smile is distinguished from a “fake” or polite smile by the narrowed eyes, and “crow’s feet” at the corner of the eyes. If someone gives us a Duchenne smile, it can trigger a genuine smile in return—and when we smile, we actually feel happier. Psychologists call this the “facial feedback hypothesis.” Putting on a happy face makes us happy and, as in this instance, can result from another’s smile.
3. Eyebrow Flash.
The eyebrow flash is that quick raising of the eyebrows that often occurs when we recognize someone. Or it can be a sign of greeting (when accompanied by a head nod). If someone eyebrow flashes us, it can cause a cognitive reaction—“Do I know this person?”—and can trigger a return eyebrow flash.
4. Personal Space Invasion.
We carry a “bubble” of personal space around us. If someone enters our bubble, it causes immediate arousal. How we interpret that arousal, and how we react, depends on our assessment of the situation. If the space invasion is from a paramour or loved one, we are likely to respond positively. However, a stranger invading our personal space can trigger irritation or fear. In those instances, we typically move away to try to protect our personal space. This is one reason we feel arousal when crowded into an elevator with strangers.
Similar to personal space invasion, direct eye contact from another can also trigger arousal. How we interpret that arousal depends on who is doing the gazing, and our circumstances. There is a social rule, or norm, that allows us to make eye contact with others but not to hold it too long. A stranger who stares at us is often viewed as a threat. We see this also in apes and other social animals (monkeys, dogs)—a direct stare can cause the animal to become agitated or threatened. Of course, if the person gazing at us is a lover (or potential lover), we can interpret eye contact as sign of interest and attraction. ("She (or he) held her gaze a bit too long; she’s interested!")
Touch from others can trigger a host of reactions. In one interesting study, waitresses in restaurants either lightly touched or did not touch their customers' arms when giving them their bills—and touching led to a higher tip. A touch or hug from someone we like or love can trigger the release of oxytocin—known as the “love hormone”—and lead to feelings of both sexual attraction and bonding.
There are many reasons why someone might let out a sigh—sadness, longing, exhaustion, boredom, or frustration. But how does a sigh affect others? It typically leads to the question, “What is wrong?” We immediately want to know why a friend or loved one let out this nonverbal cue, likely because we understand the myriad reasons why someone might sigh. In any event, it gets our attention.
There is little research on the shrug, but I suspect that it creates complex reactions in others. I've noticed that presidential candidate Donald Trump often shrugs when someone confronts him on a “half-truth” or when he in criticized over something controversial he has said. His shrug has a “so what?” quality that actually often stops the criticism, as it seems to have the effect of psychologically “disarming” people.