title: Moon illusion simulated in complete darkness: planetarium experiment reexamined.
abstract: In 1962, Kaufman and Rock reported that the moon illusion did not occur in the darkness of a planetarium or in a completely dark room. The present study reexamined their findings. Two pairs of light points, separated by 3.5 degrees, were presented on the dome screen of a planetarium. Subjects compared the distance between the two light points presented in the horizontal direction with the distance between the two light points at the zenith. Three illumination conditions were used: The inside of the planetarium was completely dark, was lighted, or was projected with the silhouette of a city under a starry sky. The effect of eye elevation on the illusion was also examined. Contrary to Kaufman and Rock's results, a size discrepancy comparable to the moon illusion was obtained in the horizon-and-stars condition and even in the complete-darkness condition. Little or no illusion was obtained in the lighted-room condition. The results also showed that eye elevation affected the magnitude of the illusion.
authors.affiliation: Department of Psychology, Faculty of Humanities, Niigata University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Suzuki
mesh_terms: D003463:Cues; D003624:Darkness; D005133:Eye Movements; D005556:Form Perception; D006801:Humans; D008027:Light; D016081:Moon; D009903:Optical Illusions; D012107:Research Design; D012858:Size Perception