ABSTRACT
J. Plateau was the first to indicate how a power law might be a better predictor of psychophysical judgments than Gustav Theodor Fechner’s logarithmic law. A logarithmic law has units of sensation-magnitude that are psychologically equal as stimulus intensity increases geometrically. According to Donald Laming, the removal of the notion that thresholds had to be “fixed” in psychophysical tasks was associated with the rise of signal detection theory. The idea that some continuous psychophysical functions might be the outcome of prior discrete processes involving entities called “quanta” (of which Einstein’s photons are examples) was successfully introduced into sensory physiology in the early twentieth century. Nevertheless, by the first decades of the twenty-first century, neuroscientists and psychologists amassed an enormous database of knowledge concerning mind/brain interactions. Fechner was impressed by J. F. Herbart’s theory, and adopted Herbart’s word Schwelle (“threshold”) into his psychophysics.
