Benham’s Top – Colour from time & space

From Michael’s “Optical Illusions & Visual Phenomena”

What to do – On the right the “Benham Disk” spins, initially quite slowly. Click repeatedly on the appropriate button to change rotation speed or direction.

What not to observe – The higher the speed, the more stroboscopic artifacts occur due to the interaction of your monitor’s frame rate and the frame-wise display of the rotating wheel (think of the backwards rotating spike wheels in Western movies).

What to observe – When a fairly high speed (more precisely: local temporal flicker frequency) is reached, the arcs take on weak (desaturated) colours, for instance I see a red-brown in the centre three arcs. When reversing the direction of rotation, the colours flip places.

Comment — Benham’s top is a classic examples of subjective colours. Because of the interaction of space and time Campenhausen calls them “pattern-induced flicker colours”. While nobody knows for certain why the colours appear, lateral inhibition and the different rates of stimulation for the colour-specific retinal ganglion cells clearly are involved. They code the pattern of light in space and time into patterns of nerve firings in space and time.
Fechner (1838) was the first to describe this phenomenon. In 1894, toy maker CE Benham discovered that a spinning disk with a particular pattern of black and white marks (more intricate than Fechner’s) could cause people to see colours. He called his disk an “Artificial Spectrum Top” and sold it through Messrs. Newton and Co. From this derives the name “Benham’s Top”.

Sources

Adamczak W (1981) The amacrine cells as an important processing site of pattern-induced flicker colors. Vision Res 21:1639–1642

Benham CE (1895) The artificial spectrum top. Nature 2:321
Benham CE (1894) The artificial spectrum top. Nature 51:113-114
Benham CE (1894) The artificial spectrum top. Nature 51:200

“An "Artificial Spectrum Top," devised by Mr. C.E. Benham, and sold by Messrs. Newton and Co., furnishes an interesting phenomenon to students of physiology optics. The top consists of a disc, one half of which is black, while the other half has twelve arcs of concentric circles drawn upon it. Each arc subtends an angle of forty-five degrees. In the first quadrant there are three such concentric arcs, in the next three more, and so on ; the only difference being that the arcs are parts of circles of which the radii increase in arithmetical progression. Each quadrant thus contains a group of arcs differing in length from those of the other quadrants. The curious point is that when this disc is revolved, the impression of concentric circles of different colors is produced upon the retina. If the direction of rotation is reversed, the order of these tints is also reversed. The cause of these appearances does not appear to have been exactly worked out.” [source]

Cohen J, Gordon DA (1949) The Prevost-Fechner-Benham Subjective Colors. Psychol Bull 46:97–136

Festinger L, Allyn MR, White C W (1971) The Perception of Color with Achromatic Stimulation. Vision Res 11:591–612

Christoph von Campenhausen & Jürgen Schramme (1995) 100 years of Benham’s top in colour science. Perception 24:695–717

Fechner GT (1838) Ueber eine Scheibe zur Erzeugung subjectiver Farben. In: Poggendorf JC (ed.) Annalen der Physik und Chemie pp 227–232 · Verlag von Johann Ambrosius Barth, Leipzig

Fechner Illusion, Essex University

Le Rohellec J, Viénot F (2001) Interaction of luminance and spectral adaptation upon Benham subjective colours. COLOR research and application, 26:S174–S179

Kenyon GT, Hilla D, Theilerb J, Georgea JS, Marshak DW (2004)A theory of the Benham Top based on center–surround interactions in the parvocellular pathway. Neural Networks 17:773–786 [PDF]