Smiling, Emotional States, and Neuroscience

Smiling is a complex activity. Let’s explore smiling, emotional states, and neuroscience.

Smiling Defined

What’s in a smile? Loaded question.

A smile is a means to communicate information from the person smiling to the world outside of the smiling person.

A smile is a facial expression. Many muscles are involved in smiling. I leave it to an expert to help us recall what muscles are involved in facial expressions:

Dr. Ryan Gross of mentaldental.com

Head & Neck Anatomy: Muscles of Facial Expression

Types of Smiles

Common knowledge tells us that smiles can convey layered emotions. A smile can convey contempt, happiness, romantic affiliation, and a myriad of other emotional expressions. And, the characteristics of different smiles can be defined.

Take a moment to read about the science of different smiles from Dr. Paul Ekman’s website:

https://www.paulekman.com/blog/science-of-smiling/

The Science of Smiling

Smiling, Perceiving Emotionality, and Neuroscience

Efthimiou et al (2024) conducted a study to assess if the facial expression espoused by a person affects how they perceive the emotional valence of facial expressions of people they are seeing. Employing electrical stimulation of the zygomaticus major muscle, one of the muscles implicated in smiling, the authors assessed how this controllable induction of a “weak” smile influences the perception of ambiguous facial expressions. Yes, in fact, there is an impact. The ambiguous expressions were more likely to be perceived as happy as compared to in the absence of the electrical stimulation in the same subject. The researchers admit to limitations in their study. Notwithstanding those limitations, their results are relevant for our interactions with each other.

Obayashi et al (2024) in a separate study determined that the amount of smiling by a speaker was correlated with the amount of smiling by a listener. The study employed very different techniques compared to the Efthimiou et al study and is as elegant as the Efthimiou et al research.

Stark et al (2019) conducted research using fMRI to explore the networks underlying how human beings learn the emotionality of infants. Human beings tend to be drawn to smile in the presence of infants, particularly if infants exude a positive emotional valence expression. A variable to consider is the cuteness factor which influences the interaction of the adult with the infant. Yes, an infant with a positive emotional expression is deemed “cuter”. It is important to consider the underlying network leading to an adult learning the temperament of the infant because adults are caregivers. A caregiver must focus attention on the infant’s emotional cues and respond to those cues. The caregiver must be able to discern changes in the emotional state and stress level of the infant and then provide emotional support to the infant. The caregiver, as noted in the article, must be aware of the infant’s attachment style and to respond accordingly. The statistical analyses in the article are complicated. The article is worth a read. The authors conclude that the network subsuming this learning process in adults involves the orbitofrontal cortex; the parahippocampus; the hippocampus; and the amygdala.

Voilà. Definitely only a cursory review of the literature related to facial expressions and emotional expressions.

The literature on emotion contained in facial expressions and its effects on the surrounding beings is burgeoning, with much more to be uncovered.

Take-aways: Smiling and facial expressions

The salience of facial expressions is their impact on our emotional lives. Like it or not, the facial expression you wear affects you and everyone around you.

As a wise woman used to say when I adopted a pouting expression: wipe that expression off your face or when the wind blows,  the expression will be etched on your face forever. Intuitively, that wise woman recognized the extent to which my facial expression could affect my world, for a long time.

Consider the ramifications of wearing a cheery and welcoming facial expression.

The Bergmans said it succinctly in the lyrics of this song performed by Barbra Streisand:

That Face

Be happy. Share your cheer with the world: you may even help someone with a dominating smile or a smile of contempt convert that smile into a coordination smile or even into a listener response smile. It certainly cannot hurt to try.

Happy January 2025.

Disclaimer: This post is not meant to substitute for a consultation with your mental health professional team.

If you are having thoughts to hurt yourself or somebody else, please call 9-1-1 or 9-8-8; or go to the nearest emergency room.

Selected References:

Efthimiou, T.N., Baker, J., Clarke, A., Elsenaar, A., Mehu, M., Korb, S. (2024). Zygomaticus activation through facial neuromuscular electrical stimulation (fNMES) induces happiness perception in ambiguous facial expressions and affects neural correlates of face processing. Social Cognitive and Affective Neuroscience, Volume 19, Issue 1. Accessed online on January 5, 2025, at https://academic.oup.com/scan/article/19/1/nsae013/7604386

Obayashi, Y., Uehara, S., Yuasa, A., Otaka, Y. (August 8, 2024). The other person’s smiling amount affects one’s smiling response during face-to-face conversations. Front. Behav. Neurosc., Volume 18. Accessed online on January 5, 2025, at https://www.frontiersin.org/journals/behavioral-neuroscience/articles/10.3389/fnbeh.2024.1420361/full

Stark, E.A., Cabral, J., Riem, M.M.E., Jzendoorn, M.H.V.I., Stein, A., Kringelbach, M.L. (December 12, 2019). The Power of Smiling: The Adult Brain Networks Underlying Learned Infant Emotionality. Cereb. Cortex, 30(4): 2019-2029. Accessed online on January 5, 2025, at https://pmc.ncbi.nlm.nih.gov/articles/PMC7297298/

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