Each of these hypotheses calls for a different investigative approach. Specifically, in order to examine the efficacy perspective, I did a survey of recent literature and synthesized the findings of scientific research reports addressing the relationship of educational psychology to the quality of teaching. Second, to investigate the plausibility of the professionalization perspective, I drew on histories of psychology and histories of teacher education as well as professionalization theories in order to assess the historical role educational psychology has played in professionalization. Third, in order to examine the policy/management explanation, I took a genealogical approach to the relationship of psychology and teacher education as disciplines in the epistemological context of modern social sciences. Finally, in order to examine the role and function of habit, I turned to John Dewey's (1921) philosophy in Human Nature and Conduct.