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Want to Spread Good Vibes? Smile and Keep Nodding "Yes"

Genuine smiles combined with "yes" nods can generate an emotional contagion.

We all know that "service with a smile" makes us feel good. But what about nodding our heads? New customer service research shows that a genuine "Duchenne" smile combined with repeated "down-nods" is a universal way to spread contagious feelings of warmth and friendliness.

 Wikipedia/Creative Commons
A Duchenne smile engages the muscles around the mouth and eyes.
Source: Wikipedia/Creative Commons

This nodding and smiling combo is referred to by the researchers as "smile-nod coupling." These findings (Woo & Chan, 2019) were published on December 23 in the journal Annals of Tourism Research.

What are down-nods and a Duchenne smile? "Down-nods" involve moving the head up-and-down in a vertical motion; the term is used interchangeably here with "yes" nods. A Duchenne smile (i.e., "smiling with your eyes") is a genuine-looking smile that involves contracting facial muscles that raise the corners of the mouth and shows teeth but also engages muscles that lift the cheeks and forms happy "smile lines" around the eyes.

According to the researchers, the contagious benefits of "service with a smile" has been researched extensively, but nonverbal down-nods are an "under-researched social cue." To the best of my knowledge, this is the first study to investigate smile-nod coupling as a possible emotional contagion.

This research took place in Hong Kong and addressed some cultural differences between East and West. As the authors explain, "In some parts of Asia, or Chinese culture, in particular, it is not smiling but nodding that matters most in interpersonal relationships. Taking into account the undue focus of smiling as a dominant physiological marker in promoting authenticity and immediacy in the West, and the prevailing use of nodding in Chinese culture, we consider both nonverbal cues in this study."

Although this study focuses on the efficacy of "service with a smile" combined with "down-nods" through the lens of optimizing employee-customer dynamics, the research has widespread implications.

Nonverbal communication plays a fundamental role in every face-to-face social interaction we have in our daily lives. Another recent study (Osugi & Kawahara, 2017) on nonverbal social cues by researchers in Japan found that "yes" nods made people seem more likable and approachable than side-to-side head movements that imply "no."

What Is Emotional Contagion?

Source: VLADGRIN/Shutterstock

"Emotional contagion" is a term used to describe the phenomenon of emotions being transferred between individuals or groups of people. According to emotional contagion theory, people tend to mimic facial expressions and body language during one-on-one social interactions and thereby "catch" others' emotions.

Most customer service experts agree that the ability of a frontline employee who interacts with the public to "infect" others with positive emotions is an asset that creates an emotional upward spiral for all parties involved. Positive employee-customer rapport makes everyone feel good.

In their recent study (2019) on smile-nod coupling as emotional contagion, Ka-shing Woo of the Open University of Hong Kong and co-author Bobbie Chan focused on the exact type of smiles and nodding that created the most warmth and friendliness between two people.

To conduct this study, the researchers trained actors to nod their heads at different speeds and in various directions while grinning with an "authentic" (i.e., Duchenne smile) or a "phony" non-Duchenne smile. Then, the actors assumed the roles of customer service employees, who interacted with real-world customers while being videotaped.

The actors spent a week rehearsing the "natural onset and offset of muscle movement for Duchenne smile" (i.e., with cheeks raised, teeth showing, and wrinkles around the eye corners) and were coached to avoid "small and rapid" head movements while down-nodding. Previous research has shown that slow, vertical head-nodding projects supportiveness, and indicates that the listener is paying attention.

After analyzing the videotapes and having study participants fill out questionnaires, Woo and Chan found that "phony" non-Duchenne smiles didn't create a positive emotional contagion. This study also confirmed that slower "yes" nods combined with a genuine Duchenne smile are a potent emotional contagion that is a catalyst for reciprocal feelings of warmth and friendliness.

"The significant interaction effect of Duchenne smile and repeated down-nods is not surprising," the authors said— "This is consistent with the Western literature that both smiling and nodding are composite factors of positive indicators of altercentrism. Altercentrism can be broken down as alter (other) and centrism (to be centered on) and describes the ability to show interest, concern, and attention to another person during social interactions.

We All Have the Power to "Infect" One Another with Emotional Contagions

Service industry employees are expected to display positive emotions during every customer interaction. But emotional contagions are a two-way street; all too often, cantankerous customers spread bad vibes that are also contagious.

As someone who's worked a variety of service industry jobs throughout my life, I know from first-hand experience what a drag it is to wait on grouchy customers who are oozing toxic emotions. Even when a customer doesn't say anything rude, if he or she is giving off cold, prickly nonverbal cues, it makes "service with a genuine smile" challenging.

As a parent, one "social etiquette rule" that I'm fanatical about with my 12-year-old daughter is the paramount importance of being super polite and thankful to every service industry worker. She knows the verbal cues well: in our family, we always say "thank you" whenever a food server brings anything to the table or a busboy refills our water glasses. But the etiquette of nonverbal cues can be ambiguous, and hard to pin down.

The new findings on smile-nod coupling created a great parent-child teaching moment about the contagiousness of emotions. Yesterday morning, over a buffet breakfast at a ski lodge, I summarized the findings of this study and told my daughter about the ricochet effect of feel-good vibes created by Duchenne smiles combined with slow "yes" nods.

At dinner last night, the restaurant was a mob scene. Our waiter was in the weeds and seemed frazzled. He didn't look very happy. Without any coaching, the moment our server approached the table, my daughter gave him a genuine Duchenne smile and a few friendly down-nods. I was also nodding and smiling. Within a few seconds, it seemed like our server "caught" some positive emotions and was giving off warmer and friendlier nonverbal cues, too.

Remember: Any time you want to spread feelings of warmth and friendliness, one way to kickstart positive emotional contagions is through repeated down-nods combined with a Duchenne smile that engages the muscles around your mouth and eyes.


Ka-shing Woo and Bobbie Chan. "'Service with a Smile' and Emotional Contagion: A Replication and Extension Study." Annals of Tourism Research (First published online: December 23, 2019) DOI: 10.1016/j.annals.2019.102850