The idea of psychophysical law comes from the discovery made by astronomers at the beginning of the 19th century that the relation between measures of sensation of stellar brightness obtained by Hipparchus of Rhodes around 150 B.C. and measures of the corresponding quantity of light is approximately logarithmic. Fechner proposed that this logarithmic relation applied to each sensation. As an alternative psychophysical law, Plateau proposed the power law. However, in the second half of the 20th century, it became increasingly clear that psychophysical laws are arbitrary. Anderson\u2019s information integration theory overcomes this indeterminacy and redefines the objectives of psychophysics for the 21st century. Such objectives are the measu...