Ponzo Illusion


The Ponzo illusion is a geometrical-optical illusion which¬†was first demonstrated by the Italian psychologist Mario Ponzo in 1911. He suggested that the human mind judges an object’s size based on its background. He showed this by drawing two identical lines across a pair of converging lines, similar to railway tracks. The upper line looks longer because we interpret the converging sides as parallel lines receding into the distance.