Nick Haslam makes a serious case for studying it:
In 30 years of studying the field I rarely came across any recognition that human beings are creatures who excrete. Much of what we psychologists care about is on the mental side of the mind/body divide, but even when we go corporeal we eliminate elimination. Psychologists have examined the psychobiology of eating, sleeping and sex at great length, and devoted numerous journals and professional associations to them. We have investigated how substances cross from outer to inner but largely ignored traffic in the other direction.