Abstract
When looking at faces, we readily extract a variety of social properties — from stable traits (such as trustworthiness or extraversion) to more transient states (such as surprise or anger). But one of the most important properties we can perceive from others’ faces is their attentional state — since the likelihood of someone in our local environment affecting our fitness is enhanced when they are attentive. But just how can we tell whether another person is attentive (vs. distracted)? Some cues (such as direct gaze) may be relatively straightforward, but others may be more subtle and non-intuitive. We explored this using reverse correlation, a data-driven approach that can reveal the nature of internal representations without prior assumptions. Observers viewed pairs of faces created by adding randomly generated noise (across many spatial frequencies) to a constant base face, and had to select which appeared to be most attentive. Analyses of automatically extracted facial landmarks from the resulting ‘classification images’ revealed the determinants of perceived attentiveness. Some cues were straightforward: attentive faces had more direct eye gaze, and larger pupils. But other equally robust cues seemed less intuitive: for example, attentive faces also had smaller mouths — perhaps because attention is correlated with more global facial expressions. These results are consistent with the view that eyes and faces are prioritized during perception because of their unique informativeness about others’ mental states. And these powerful and consistent effects of facial cues on impressions of attentiveness highlight the importance of attention not just as a perceptual process, but as an object of perception itself.