"From a scientific standpoint, [the new study] seems legitimate," said Franklin, who applauds the authors for clearly discussing the limitations of their work. Researchers only tested "typically developing children" living near a major university, whose parents have good incomes. The children were also mostly white and had parents or caregivers who were willing and able to enroll them in behavioral research. The authors also noted that all of the children who participated were free from stimulant medication at the time of the study. So the findings, researchers note, can't be assumed to apply to all children.