  {G}{ustav} Fechner's 1860 delineation of psychophysics, the measurement of
sensation in relation to its stimulus, is widely considered to be the advent of
modern psychological science. In psychophysics, a researcher parametrically
varies some aspects of a stimulus, and measures the resulting changes in a
human subject's experience of that stimulus; doing so gives insight to the
determining relationship between a sensation and the physical input that evoked
it. This approach is used heavily in perceptual domains, including signal
detection, threshold measurement, and ideal observer analysis. Scientific
fields like vision science have always leaned heavily on the methods and
procedures of psychophysics, but there is now growing appreciation of them by
machine learning researchers, sparked by widening overlap between biological
and artificial perception \cite{rojas2011automatic,
scheirer2014perceptual,escalera2014chalearn,zhang2018agil,
grieggs2021measuring}. Machine perception that is guided by behavioral
measurements, as opposed to guidance restricted to arbitrarily assigned human
labels, has significant potential to fuel further progress in artificial
intelligence.
