http://www.cns.nyu.edu/~msl/courses/0044/handouts/Weber.pdf

gi

general relationship between the initial intensity of something and the smallest detectable increment is exactly what Weber noticed and formalized into “Weber’s Law”.

Another take on this is http://spectrum.ieee.org/podcast/biomedical/bionics/does-the-brain-work-logarithmically Relevant: about how easy it is to point at stuff I need a category for the intersection between Psychology and mathematical laws