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Iperception. 2015 Aug 21;6(4):2041669515593043. doi: 10.1177/2041669515593043. eCollection 2015 Aug.

A Refresher of the Original Bloch's Law Paper (Bloch, July 1885).

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Laboratoire Psychologie de la Perception, Université Paris Descartes and CNRS, Paris, France.


In 1885, Adolphe-Moïse Bloch asked the following simple question "Is there a law describing the relationship between the duration of a light and its perceived intensity?" Based on a series of experiments using a Foucault regulator and a candle, Bloch concluded that "when the lighting duration varies from 0.00173 to 0.0518 seconds (…) the [visible] light is markedly in inverse proportion to its duration"-his famous law. As this law pertains to the more general and hotly debated question of accumulation of sensory information over time, it is timely to offer the public a full translation of Bloch's original paper (from French) and to present it within the context of contemporary research.


detection; drift-diffusion; information accumulation; linear systems; temporal integration; transfer function

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