Ever wonder if someone’s into you? Discover how your eyes reveal attraction—and what science says about those lingering glances.

1 Institut National de la Santé et de la Recherche Médicale (INSERM) UMR_S933, Université Pierre et Marie Curie (UPMC) - Paris 6; and Assistance Publique-Hôpitaux de Paris (AP-HP), Hôpital ...