This element of design is Negative Space. The hand isn't actually holding anything. It implies that there is a light bulb in the empty space. Negative space guides your imagination to finish the image.
hueandsaturation: “ The Daily Beast cover illustration. Alfred Hitchcock: The Psycho Genius of Hollywood. “To say he’s making a comeback would be misleading, because he never went away. Alfred Hitchcock’s place in the pantheon of great directors has.