Mental age According to Stern, a composite score reflecting all the levels of the Binet–Simon test that a child could successfully pass.
Mental orthopedics The exercises that Binet suggested for enhancing determination, attention, and discipline. These procedures would prepare a child for formal education.
Natural selection A key concept in Darwin’s theory of evolution. Because more members of a species are born than environmental resources can support, nature selects those with characteristics most conducive to survival under the circumstances, which allows them to reproduce.
Nature–nurture controversy The debate over the extent to which important attributes are inherited or learned.
Pearson, Karl (1857–1936) Devised the formula for calculating the coefficient of correlation.
Social Darwinism Spencer’s contention that, if given freedom to compete in society, the ablest individuals will succeed and the weaker ones will fail, and this is as it should be.