Wechsler Ault Intelligence Scale (WAIS) is a general test of intelligence (IQ), published in February 1955 as a revision of the Wechsler-Bellevue test (1939), a battery of tests that is composed from subtests Wechsler "adopted" from the Army Tests (Yerkes, 1921). Wechsler defined intelligence as "The global capacity of a person to act purposefully, to think rationally, and to deal effectively with his/her environment."