One of the world's most famous pyramids is not located in Egypt but is on a music album cover by the band Pink Floyd. However, not a pyramid but a prism, the iconic image of a beam of light turning into a rainbow is a powerful symbol that captures the complexities of colour perception across cultures and individuals. This study examines how…

Reports effects of context that are entirely perceptual. Visual discrimination was enhanced when line segments were flashed in a region that was perceived as a figure. Discrimination was substantially degraded when the same region was seen as ground although the physical stimulus remained identical throughout figure-ground reversals. (Author/JN)