Mandatory First Impressions: Happy Expressions Increase Trustworthiness Ratings of Subsequent Neutral Images

Abstract

First impressions of traits are formed rapidly and nonconsciously, suggesting an automatic process. We examined whether first impressions of trustworthiness are mandatory, another component of automaticity in face processing. In Experiment 1a, participants rated faces displaying subtle happy, subtle angry, and neutral expressions on trustworthiness. Happy faces were rated as more trustworthy than neutral faces; angry faces were rated as less trustworthy. In Experiment 1b, participants learned eight identities, half showing subtle happy and half showing subtle angry expressions. They then rated neutral images of these same identities (plus four novel neutral faces) on trustworthiness. Multilevel modeling analyses showed that identities previously shown with subtle expressions of happiness were rated as more trustworthy than novel identities. There was no effect of previously seen subtle angry expressions on ratings of trustworthiness. Mandatory first impressions based on subtle facial expressions were also reflected in two ratings designed to assess real-world outcomes. Participants indicated that they were more likely to vote for identities that had posed happy expressions and more likely to loan them money. These findings demonstrate that first impressions of trustworthiness based on previously seen subtle happy, but not angry, expressions are mandatory and are likely to have behavioral consequences.

The cultural learning account of first impressions

“…Similarly, first impressions of faces are thought to be automatic (hard to inhibit) [36,79]. For example, impressions of faces influence the evaluation of voices even when participants have been asked to ignore them [36].…”

Face masks have a limited influence on first impressions: evidence from three experiments

“…Participants were asked to rate each facial image (not identity) on trustworthiness using a 7-point scale ranging from 1 ( not at all trustworthy ) to 7 ( extremely trustworthy ). To keep the methods consistent with our original protocol, participants were asked two additional questions about each identity (see Thierry et al, 2021); we did not analyse these additional measures for this experiment.…”

“…There were three images of each identity, each displaying either a neutral, happy, or angry expression. As in Thierry et al (2021), we presented subtle expressions (40% expression; 60% neutral) by morphing the neutral image of each identity with the happy and angry images. We used Photoshop to superimpose a surgical mask on each face.…”

“…Previous research looking at the automaticity of first impressions found that first impressions based on expressions of happiness, but not anger, are mandatory (Thierry et al, 2021). In that study, participants studied a set of faces that displayed a happy or an angry expression in the learning phase.…”

“…In Experiment 1, participants rated the trustworthiness of young adult faces. We examined whether mandatory first impressions based on previous displays of happiness (Thierry et al, 2021) are disrupted by facial masks. In Experiment 2, participants provided interpretations of ambiguous situations in which a target child's behaviour or the intention behind their misbehaviour was ambiguous.…”