As pointed out in the article "Virtual Space – the movies of the future" in real life the 3D effect, or stereoscopic vision, depends on the distance between the eyes, which is only about 2 1/2 inches. The depth perception this affords is only noticeable near to the head – at about arms length. It is only useful for such tasks as threading a needle. It follows that in films portraying real life, where nothing is ever shown so close to the camera, the 3D effect is not noticeable and is soon forgotten as the film proceeds.