The subjective value of a smile alters social behaviour.

Erin A Heerey,Thandiwe S E Gilder,Marina A Pavlova

doi:10.1371/journal.pone.0225284

Abstract

Face-to-face social behaviour is difficult to explain, leading some researchers to call it the “dark matter” of psychology/neuroscience [1]. We apply an idea from neuroeconomics to this problem, suggesting that how people subjectively value facial expressions should predict usage differences during unconstrained interaction. Specifically, we ask whether the subjective value of smiles is malleable as a consequence of immediate social experience and how this relates to smiling during face-to-face interactions. We measured the value of a smile in monetary terms and found that increases in people’s social neediness caused devaluation of polite smiles but no changes in how they valued genuine smiles. This result predicts that participants induced to feel high levels of social need should be less responsive to their social partners’ polite smiles in a subsequent unconstrained social interaction. As expected, high social-need participants returned fewer polite smiles when interacting with a partner, leading to poor interaction outcomes. Genuine smile reciprocity remained unchanged. Findings show that social states influence real-world interactions by changing social-cue valuation, highlighting a potential mechanism for understanding the moment-to-moment control of social behaviour and how behaviour changes based on people’s subjective evaluations of the social environment.

Highlights

Genuine smiles of pleasure are rewarding social cues that cause positive feelings in receivers and lead people to anticipate positive social outcomes [2,3,4]
Not typically considered rewarding [3, 8], polite smiles are important social tokens [9]. Both genuine and polite smiles are highly likely to be reciprocated in face-to-face social interactions and good smile reciprocity enhances liking for a social partner [10,11,12]
Because genuine and polite smiles are typically compared to each other, rather than to a neutral/control condition (e.g., [29, 34]), it remains unclear whether rejection-induced changes in social state alter the value of genuine smiles, polite smiles, or both

Summary

Introduction

Genuine smiles of pleasure are rewarding social cues that cause positive feelings in receivers and lead people to anticipate positive social outcomes [2,3,4]. Because genuine and polite smiles are typically compared to each other, rather than to a neutral/control condition (e.g., [29, 34]), it remains unclear whether rejection-induced changes in social state alter the value of genuine smiles, polite smiles, or both This is an important question because it speaks directly to a possible mechanism by which social state changes may alter face-to-face social behaviour and subsequent social outcomes after enduring a social rejection [18, 19, 21, 22, 35, 36]. This method is advantageous to simple preference reporting, because it enables precise quantification of relative preferences for one stimulus dimension (e.g., brand-name) standardized in terms of the other dimension (e.g., cost) Our version of this task uses a set of faces that provide monetary reinforcement with either higher or lower frequency and give different types of social feedback believed to vary in subjective value [38, 40]. We begin by quantifying how social state (e.g., feeling rejected versus accepted by a future social partner) influences the subjective value of smiles

Participants

Findings

Procedure