The Venus effect is a phenomenon in the psychology of perception, named after various paintings of Venus gazing into a mirror, such as Diego Velázquez's Rokeby Venus, Titian's Venus with a mirror, and Veronese's Venus with a mirror. Viewers of such paintings assume that Venus is admiring her own reflection in the mirror; however, since the viewer sees her face in the mirror, Venus is actually looking at the reflection of the painter.[1]
This psychological effect is often used in the cinema, where an actor will be shown apparently looking at himself or herself in the mirror. What viewers see is different from what the actor sees, because the camera is not right behind the actor, but the position of the actor is often chosen so that his or her image is nicely framed in the mirror for the camera.
Although the name of the effect refers to a woman, Venus, the effect is more general. A beautiful example in which an animal is seen as looking at itself in a mirror is The Lady and the Unicorn (French: La Dame à la licorne). Note that the effect is about how people interpret the image and this is documented by the Wikipedia entry: "The unicorn kneels on the ground, with his front legs in the lady's lap, from which he gazes at his reflection in the mirror."
Bertamini et al. (2010) conducted additional studies and confirmed that the Venus effect also occurs with photographs, and in real life when the person and the mirror are seen in a room.[2]