He teaches courses on human development, cross-cultural psychology, diversity and persons & systems. Committed to interdisciplinary teaching, he is a member and past-president of the Association for Interdisciplinary Studies. Nelson has done research in Japan on early day care programs, human services systems and juvenile delinquency, on young adult development among Earlham students, and on the influence of family history on personal identity. He has also presented a paper on diversity at an international conference in Belfast.