Unconscious pupillometry: An effect of “attentional contagion” in the absence of visual awareness.

When looking at other people, we can readily tell how attentive (or distracted) they are. Some cues to this are fairly obvious (as when someone stares intensely at you), but others seem more subtle. For example, increased cognitive load or emotional arousal causes one's pupils to dilate. This phenomenon is frequently employed as a physiological measure of arousal, in studies of pupillometry. Here, in contrast, we employ it as a stimulus for...