In addition, Festinger is credited with the ascendancy of laboratory experimentation in social psychology as one who "converted the experiment into a powerful scientific instrument with a central role in the search for knowledge." An obituary published by the "American Psychologist" stated that it was "doubtful that experimental psychology would exist at all" without Festinger. Yet it seems that Festinger was wary about burdensome demands for greater empirical precision. Warning against the dangers of such demands when theoretical concepts are not yet fully developed, Festinger stated, "Research can increasingly address itself to minor unclarities in prior research rather than to larger issues; people can lose sight of the basic problems because the field becomes defined by the ongoing research." He also stressed that laboratory experimentation "cannot exist by itself," but that "there should be an active interrelation between laboratory experimentation and the study of real-life situations." Also, while Festinger is praised for his theoretical rigor and experimental approach to social psychology, he is regarded as having contributed to "the estrangement between basic and applied social psychology in the United States." He "became a symbol of the tough-minded, theory-oriented, pure experimental scientist," while Ron Lippitt, a fellow faculty member at Lewin's Research Center for Group Dynamics with whom Festinger often clashed, "became a symbol of the fuzzy-minded, do-gooder, practitioner of applied social psychology."