Binocular Cue

One instance of a binocular cue is convergence. This says that as an object gets closer to our face, our eyes must move toward each other to keep focused on the object.

Everyone can relate to this binocular cue as we have all held a pencil in front of our faces and moved the object closer and closer to our faces until we become cross-eyed. This occurs because in order to remain focused on an object which is closer to our faces, our eyes must move toward each other to keep it in focus. This is most likely the most infamous instance of convergence: