Brain Power

After decades of conflicting beliefs about the intellectual capacity of young adolescents, scholars see a growing consensus, backed by research, that middle school students' brains are ready for learning.

The National Middle School Association's own mission statement, written in 1982, cautioned against setting expectations too high for 12- to 14-year-olds. Instead, educators should emphasize "learning new facts and information within the profile of thinking skills initiated prior to this plateau period" of brain growth, said the guiding force behind the middle school concept.

But scientists are discovering that early adolescents' brains are undergoing profound changes that are not only a necessary part of growing up, but also signal a shift in...