Bowd, A. D. 1980. Ethics and animal experimentation. American Psychologist 35, 224-225.

The researcher's central dilemma exists in an especially acute form in psychology: either the animal is not like us, in which case there is no reason for performing the experiment; or else the animal is like us, in which case we ought not to perform an experiment ... which would be considered outrageous if performed on one of us.(quote from Singer P Animal Liberation, New York: New York Review Books, 1975)