Beginning less than a century ago within a historical, economic, and legal framework, systematic research on the family shifted in the 1920's to the standpoints of social interaction and cultural change. Since then the social interactional frame of reference has been enlarged as the result of influences from psycho-analysis and cultural anthropology. This has led to collaborative research on an interdisciplinary basis and a growing interest in fundamental problems. As regards method, the trend toward quantification is notable.