The results of the author's studies qualify the conclusions of Piaget and Inhelder which demonstrated formal-stage thinking to be the rule in adolescence. Two

of the formal-stage experiments of Piaget and Inhelder were replicated with groups of average adolescents and adults and groups of gifted adolescents. Only twenty to thirty-five percent of the average population functioned at the fully formal level, while seventy-five percent of a group of scientifically gifted older adolescent boys achieved full formal level functioning. Thus formal-stage thinking appeared more ideal than typical, a potential only partially attained by most.