Judging trustworthiness from faces: Emotion cues modulate trustworthiness judgments in young children.

By adulthood, people judge trustworthiness from appearances rapidly and reliably. However, we know little about these judgments in children. This novel study investigates the developmental trajectory of explicit trust judgments from faces, and the contribution made by emotion cues across age groups. Five-, 7-, 10-year-olds, and adults rated the trustworthiness of trustworthy and untrustworthy faces with neutral expressions. The same participants also rated faces displaying overt happy and angry expressions, allowing us to investigate whether emotion cues modulate trustworthiness judgments similarly in children and adults. Results revealed that the ability to evaluate the trustworthiness of faces emerges in childhood, but may not be adult like until 10 years of age. Moreover, we show that emotion cues modulate trust judgments in young children, as well as adults. Anger cues diminished the appearance of trustworthiness for participants from 5 years of age and happy cues increased it, although this effect did not consistently emerge until later in childhood, that is, 10 years of age. These associations also extended to more subtle emotion cues present in neutral faces. Our results indicate that young children are sensitive to facial trustworthiness, and suggest that similar expression cues modulate these judgments in children and adults.

Appearance-based trust behaviour is reduced in children with autism spectrum disorder.

Typical individuals make rapid and reliable evaluations of trustworthiness from facial appearances, which can powerfully influence behaviour. However, the same may not be true for children with autism spectrum disorder. Using an economic trust game, the current study revealed that like typical children, children with autism spectrum disorder rationally modulate their trust behaviour based on non-face cues to partner trustworthiness (e.g. reputation information). Critically, however, they are no more likely to place their trust in partners with faces that look trustworthy to them, than those that look untrustworthy. These results cannot be accounted for by any group differences in children's conceptualization of trustworthiness, ability to read trustworthiness from faces or understanding of the experimental paradigm. Instead, they seem to suggest that there may be a selective failure to spontaneously use facial cues to trustworthiness to guide behaviour in an ecologically valid context.

Perceived trustworthiness of faces drives trust behaviour in children.

Facial appearances can powerfully influence adults' trust behaviour, despite limited evidence that these cues constitute honest signals of trustworthiness. It is not clear, however, whether the same is also true for children. The current study investigated whether, like adults, 5-year-olds and 10-year-olds are more likely to place their trust in partners that look trustworthy than those that look untrustworthy. A second, closely related question was whether children also explicitly value the information from face cues when making trust decisions. We investigated these questions using Token Quest: an economic trust game that gave participants the opportunity to make investments with a series of partners who might (or might not) repay their trust with large returns. These interactions occurred under different conditions, including one in which participants were shown the face of each partner and another in which they could 'purchase' access to faces with a portion of their investment capital. Results indicated that, like adults, 10-year-old children selectively placed their trust in those partners they perceived as looking trustworthy and many were willing to 'pay' to purchase access to these face cues during the trust game. We observed a similar profile of trust behaviour in 5-year-olds, with no significant group difference in the impact of face cues on behaviour across the three age groups. Together, these findings indicate that the influence of face cues on trust behaviour emerges early, and highlight a capacity for sophisticated social cognition in young children.

Facial trustworthiness judgments in children with ASD are modulated by happy and angry emotional cues.

Appearance-based trustworthiness inferences may reflect the misinterpretation of emotional expression cues. Children and adults typically perceive faces that look happy to be relatively trustworthy and those that look angry to be relatively untrustworthy. Given reports of atypical expression perception in children with Autism Spectrum Disorder (ASD), the current study aimed to determine whether the modulation of trustworthiness judgments by emotional expression cues in children with ASD is also atypical. Cognitively-able children with and without ASD, aged 6-12 years, rated the trustworthiness of faces showing happy, angry and neutral expressions. Trust judgments in children with ASD were significantly modulated by overt happy and angry expressions, like those of typically-developing children. Furthermore, subtle emotion cues in neutral faces also influenced trust ratings of the children in both groups. These findings support a powerful influence of emotion cues on perceived trustworthiness, which even extends to children with social cognitive impairments.