Can people detect the trustworthiness of strangers based on their facial appearance?

Although cooperation can lead to mutually beneficial outcomes, cooperating only pays off for the individual if others can be trusted to cooperate as well. How do people detect trustworthy interaction partners? While people readily rely on the facial appearance of strangers to judge their trustworthiness, the question of whether these judgments are accurate remains debated. The present research examines whether having access to the facial appearance of counterparts provides a strategic advantage to participants when making trust decisions. Furthermore, we investigated whether people show above-chance accuracy in trustworthiness detection (a) when they make trust decisions vs. provide explicit trustworthiness ratings, (b) when judging male vs. female counterparts, and (c) when rating cropped images (with non-facial features removed) vs. uncropped images. Results showed that incentivized trust decisions (Study 1, n = 131) and predictions of counterparts’ trustworthiness (Study 2, n = 266) were unrelated to actual trustworthiness. Moreover, accuracy was not moderated by stimulus type (cropped vs. uncropped faces) or counterparts’ gender. Overall, these findings suggest that people are unable to detect the trustworthiness of strangers based on their facial appearance.