 Bogin said that the human brain reaches adult size when the body is only 40 percent complete, when "dental maturation is only 58 percent complete" and when "reproductive maturation is only 10 percent complete".Bogin said that this allometry of human growth allows children to have a "superficially infantile" appearance (large skull, small face, small body and sexual underdevelopment) longer than in other "mammalian species".Bogin said that this cute appearance causes a "nurturing" and "care-giving" response in "older individuals".