Gregory A. Kimble, Michael Wertheimer, Charlotte White. Portraits of Pioneers in Psychology. Psychology Press, 2013, p. 175. "Watson's outspoken atheism repelled many in Greensville."
Michael Martin. The Cambridge Companion to Atheism. Cambridge University Press, 2006, p. 310. "Among celebrity atheists with much biographical data, we find leading psychologists and psychoanalysts. We could provide a long list, including (...) John B. Watson (...)"