Broca-Sulzer effect

Brightness perception variation effect

An adaptation of the original figure published by Broca and Sulzer.[1]

The Broca-Sulzer effect or Broca-Sulzer phenomenon is an experimental observation related to the psychophysics of vision. It has two parts, temporal and spatial. In the temporal effect, the perceived brightness of a single flash of light first increases with the flash duration, then reaches a maximum, and decreases for a longer pulse. The maximum is more pronounced and is observed at shorter durations for a stronger illumination; it is reached at approximately 0.1 for a 100 lux flash.[1]

Similarly, in the spatial Broca-Sulzer effect, the perceived brightness increases with increasing angular size of the flashing object until it reaches approximately 2.5 arcminutes, and then decreases for a larger object.[2]

The Broca-Sulzer effect was reported by André Broca and David Émile Sulzer in 1902.[1] It conflicted with the 1885 report by Adolphe-Moïse Bloch who believed that the perceived brightness monotonously increases with the flash duration.[3] Later research showed that while the Bloch's law may hold for some individuals and for some experimental conditions, the Broca-Sulzer effect is a more general phenomenon.[4]

## See also[edit]

* Talbot-Plateau law

## References[edit]

1. ^ a b c Broca, André; Sulzer, D. (1902). "La sensation lumineuse en fonction du temps". Comptes Rendus des Séances de l'Académie des Sciences. 134: 831–834.
2. ^ Higgins, Kent E.; Rinalducci, Edward J. (1975). "Suprathreshold intensity-area relationships: A spatial Broca-Sulzer effect". Vision Research. 15 (1): 129–143. doi:10.1016/0042-6989(75)90071-1. PMID 1129960. S2CID 7585989.
3. ^ Bloch, A-M. (1885). "Expériences sur la vision". Comptes rendus des séances de la Société de biologie. 37 (28): 493–495.
4. ^ Rieiro, Hector; Martinez-Conde, Susana; Danielson, Andrew P.; Pardo-Vazquez, Jose L.; Srivastava, Nishit; MacKnik, Stephen L. (2012). "Optimizing the temporal dynamics of light to human perception". Proceedings of the National Academy of Sciences. 109 (48): 19828–19833. Bibcode:2012PNAS..10919828R. doi:10.1073/pnas.1213170109. PMC 3511764. PMID 23150557.