A perceptual correlate of McIlwain's "periphery effect".
D000818:Animals; D002415:Cats; D006801:Humans; D007498:Iris / Q000502:physiology; D009949:Orientation; D010775:Photic Stimulation; D011601:Psychophysics; D012160:Retina / Q000502:physiology; D012171:Retinal Vessels; D014794:Visual Fields; D014796:Visual Perception