title: Why hearts flutter: Distorted dim motions.
abstract: When a display of red spots or hearts on a blue surround is moved around under dim light, the spots appear to wobble or flutter relative to the surround (the "fluttering hearts" effect). We explain this as follows: Rods and cones both respond to the hearts. Rods are more sluggish than cones, with a latency of ∼50 ms, and they are also much more sensitive to blue than to red (the Purkinje shift; Purkinje, 1825). Thus a red spot oscillating on a blue ground produces a double image: a light spot seen by the cones, followed by a trailing dark spot seen by the rods. These interacting spots of opposite luminance polarity move like "reverse phi" (Anstis, 1970) and this generates the fluttering hearts effect. We find that hearts flutter most markedly at or near mesopic equiluminance, when the red is lighter than the blue as seen by the cones, but darker than the blue as seen by the rods. These same red/blue luminance ratios give rise to two new illusions: the ghostly twin illusion, and the reversal of red/blue grating movement.
authors: Department of Psychology, University of California, San Diego, La Jolla, CA.
authors: Stuart
authors: S
authors: Anstis
authors: Department of Psychology, University of California, San Diego, La Jolla, CA.
authors: Don
authors: D
authors: Macleod
mesh_terms: D006801:Humans; D007088:Illusions; D008027:Light; D009039:Motion Perception / Q000502:physiology*; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology*; D017948:Retinal Rod Photoreceptor Cells / Q000502:physiology*
keywords: color vision; cone vision; fluttering hearts; mesopic vision; rod vision; visual latency illusion