Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for liveness detection are disclosed. In one aspect, a method includes the actions of providing, for display on a screen to a user, a graphical item that travels along a path. The actions further include tracking a movement of an eye of the user while the graphical item travels along the path on the screen. The actions further include comparing the movement of the eye of the user to the path traveled by the graphical item. The actions further include generating an eye correlation score that reflects a correlation between the movement of the eye of the user and the path traveled by the graphical item. The actions further include determining whether the eye correlation score satisfies an eye liveness threshold score. The actions further include determining whether the user is a live person.