Dynamically engaged smiling predicts cooperation above and beyond average smiling levels

Abstract

Smiling has been conceptualized as a signal of cooperative intent, yet smiles are easy to fake.We suggest that contextually appropriate, dynamically engaged smiling imposes an attentional cost, thereby making engaged smiling a plausible "honest signal" of cooperative intent. To test this hypothesis, we analyzed data from 123 pairs of same-sex strangers having "getting-to-knowyou" conversations who subsequently played a one-shot prisoner's dilemma together. We calculated the strength of engagement in smiling using a cross-lagged auto-regressive model for dyadic data. We found that when an individual's partner (the signaler) tended to smile in a more responsive way, that individual (the receiver) was more likely to cooperate. Conversely, when a signaler tended to smile in a less responsive way, the receiver was less likely to cooperate. These effects were present over-and-above the effects of average levels of smiling and self-reported liking, which also predicted likelihood of cooperation. However, dynamically engaged smiling did not predict cooperation on the part of the signaler, suggesting that receivers weight the importance of engagement more highly than they should, or even that engaged smiling might be a manipulative display. These results illustrate how conversational dynamics can influence evolutionary signaling.

Unravelling the relation between altruistic cooperativeness trait, smiles, and cooperation: a mediation analysis

“…As Schug et al (2010) showed, cooperators display greater numbers of both positive and negative emotional expressions. The tendency of cooperators to display more Duchenne smiles, as reported in previous studies ( Mehu et al, 2007a ; Reed et al, 2012 ; Danvers and Shiota, 2018 ), may be because cooperators tend to openly express all their emotions in different scenes. For example, negative emotions expressed by cooperators in response to shared unfair situations may reflect prosocial preferences ( Fehr et al, 2002 ).…”

“…In addition to the above mediation analyses to test our main hypothesis, an analysis of the effect of dynamically engaging Duchenne smiles on cooperative behavior was conducted following the two-step approach of Danvers and Shiota (2018) , in which the actor–partner interdependence model (APIM) was used to estimate the effects of dynamically engaged Duchenne smiling during the conversation on both the signalers and receiver’s behavior in the post-conversation prisoner’s dilemma. A measure of altruistic cooperativeness was included as a covariate in our analysis model to test whether dynamically engaged Duchenne smiling affected successive cooperative behaviors after accounting for altruistic cooperativeness.…”

“…Following Danvers and Shiota (2018) , cross-lagged regression models were used to predict Duchenne smiling over time for each dyad in the first step (see Figure 2 ), in which each person served both as an actor and a partner in the statistical analyses to maximize statistical power. Duchenne smiling for each actor at a given time point was predicted from his/her own Duchenne smiling at the previous time point and the partner’s Duchenne smiling at the previous time point.…”

The human fear paradox: Affective origins of cooperative care

“…Furthermore, although results are mixed, there is some evidence that humans also display a perceptual sensitivity bias towards happy faces (Wirth & Wentura, 2020;Zsido et al, 2021). Crucially, although Grossmann and others failed to find an association between sensitivity to happy faces and infants' prosociality , there is robust evidence that experienced and displayed positive affect results in more cooperation in child and adult actors (e.g., Aknin, Van de Vondervoort, & Hamlin, 2018;Centorrino, Djemai, Hopfensitz, Milinski, & Seabright, 2015;Kushlev, Radosic, & Diener, 2022;Moore, Underwood, & Rosenhan, 1973;Rosenhan, Salovey, & Hargis, 1981), as well as observers (including in cooperative parental-care contexts) (e.g., Centorrino et al, 2015;Danvers & Shiota, 2018;Lengua & Kovacs, 2005;Scharlemann, Eckel, Kacelnik, & Wilson, 2001). Therefore, it is not only fearful infants, but also happy infants, who may evoke cooperation in others, and may, by receiving more care, themselves become more cooperative adults.…”

Fearful apes, happy apes: Is fearfulness associated with uniquely human cooperation?

“…Furthermore, although results are mixed, there is some evidence that humans also display a perceptual sensitivity bias towards happy faces (Wirth & Wentura, 2020; Zsido et al, 2021). Crucially, although Grossmann and others failed to find an association between sensitivity to happy faces and infants' prosociality (Grossmann, Missana, & Krol, 2018; Rajhans, Altvater-Mackensen, Vaish, & Grossmann, 2016), there is robust evidence that experienced and displayed positive affect results in more cooperation in child and adult actors (e.g., Aknin, Van de Vondervoort, & Hamlin, 2018; Centorrino, Djemai, Hopfensitz, Milinski, & Seabright, 2015; Isen & Levin, 1972; Kushlev, Radosic, & Diener, 2022; Moore, Underwood, & Rosenhan, 1973; Rosenhan, Salovey, & Hargis, 1981), as well as observers (including in cooperative parental-care contexts) (e.g., Centorrino et al, 2015; Danvers & Shiota, 2018; Lengua & Kovacs, 2005; Scharlemann, Eckel, Kacelnik, & Wilson, 2001). Therefore, it is not only fearful infants, but also happy infants, who may evoke cooperation in others, and may, by receiving more care, themselves become more cooperative adults.…”