Social functions of smiles and laughter
We can think of nonverbal signals as tools people use to elicit desired behaviors from others. A cry of pain elicits caregiving behavior, while a wide-eyed facial expression of fear cues other people to detect and avoid the threat. Our social functional framework for studying expressive signals classifies expressions according the social tasks they serve to accomplish, while acknowledging that they also convey information about the internal feeling state of the expresser.
When Masks Cover Expression
If facial expressive signals are so nuanced and socially useful, what happens when they are covered as is the case when people wear masks? In order to understand some of the social implications of covering the face with a mask during the COVID-19 pandemic, our on-going research examines the perception of a person’s emotion expression when they are wearing different types of masks.
citations
Langbehn, A. T., Yermol, D. A., Zhao, F., Thorstenson, C. A., & Niedenthal, P. M. (2022). Wearing N95, surgical, and cloth face masks compromises the perception of emotion. Affective science, 3(1), 105-117.
Three Types of Smiles
Below are descriptions of three tasks, which we see as fundamental to social living, that smiles and laughter can accomplish. Dr. Niedenthal and colleagues introduced these ideas in 2010, which we further explore in an Trends in Cognitive Sciences review (2017). Although we assume high variability in the physical form of smiles and laughs that accomplish each of the three tasks, we have used perceiver-based techniques to develop prototypical examples of smiles (2017) and laughter (2017) that perceivers understand as serving the social tasks (smile examples are below).
Reward
Some smiles and laughter feel good to produce and perceive, and can therefore act as social reinforcers, or rewards. We think nonverbal reward signals are especially important tools for pre-verbal infants, who use the smiles and laughter of their caregivers to shape their own behavior. By producing reward smiles and laughter, babies are also able to reinforce and maintain caregivers' attention, which is crucial for their survival. Reward expressions include what some researchers refer to as "spontaneous" or "genuine" smiles and laughter, and therefore have similar physical properties.
Affiliation
Smiles and laughter that primarily serve an affiliation function may be the most ubiquitous in everyday life. Affiliation expressions signal non-threatening, friendly intentions, and smooth over interactions. Watch for these smiles when you pass strangers on the street or get into a crowded elevator. These smiles acknowledge the presence of another person and convey benign intentions without necessarily being rewarding or signaling positive emotions. Affiliative laughter includes the chuckles and giggles that occur frequently during conversation and sound friendly but not "genuinely amused."
Dominance
Smiles and laughter convey (physical) harmlessness. Expressers sometimes embed their aggressive intentions in one of these "harmless" signals. We propose that dominance smiles and laughter elevate the social status of the expresser at least momentarily. Such smiles may be directed towards out-group members, like fans of a rival football team, but may also be directed towards in-group members who transgress a group norms. You can imagine a deep, barking laugh of derision one friend makes when another friend says something stupid. That laugh conveys momentary derision without necessarily harming the relationship. These signals are clearly not designed to elicit positive emotion in the perceiver!
REPRESENTATIVE PUBLICATIONS
Hansen, Z., Wood, A., & Niedenthal, P.M. (2023). Gender differences in the form and function of naturally occurring smiles. Forthcoming.
Langbehn, A. T., Yermol, D. A., Zhao, F., Thorstenson, C. A., & Niedenthal, P. M. (2022). Wearing N95, surgical, and cloth face masks compromises the perception of emotion. Affective Science, 3(1), 105-117.
Rychlowska, M., van der Schalk, J., Niedenthal, P., Martin, J., Carpenter, S. M., & Manstead, A. S. (2021). Dominance, reward, and affiliation smiles modulate the meaning of uncooperative or untrustworthy behaviour. Cognition and Emotion, 35(7), 1281-1301.
Martin, J. D., Wood, A., Cox, W. T., Sievert, S., Nowak, R., Gilboa-Schechtman, E., ... & Niedenthal, P. M. (2021). Evidence for distinct facial signals of reward, affiliation, and dominance from both perception and production tasks. Affective Science, 2(1), 14-30
Martin, J. D., Abercrombie, H. C., Gilboa-Schechtman, E., & Niedenthal, P. M. (2018). Functionally distinct smiles elicit different physiological responses in an evaluative context. Scientific Reports, 8(1), 3558.