Intelligence Timeline By schreder58m Jan 1, 1917 WWI intelligence testing begins Jan 1, 1919 Psychology by John B. Watson Jan 1, 1920 Classic Conditioning pulblished by Watson and Rayner Jan 1, 1925 Gestalt Theory brought to U.S. Jan 1, 1932 Jean Piaget publishes The Moral Judgement of Children Jan 1, 1935 Thematic Appreception Test Jan 1, 1939 Weschsler-Bellevue test Jan 1, 1949 Wechsler Intelligence Scale for Children Jan 1, 1955 Wechsler Adult Intelligence Scale by David Welscher Jan 1, 1963 Raymond Cattell discovers fluid and crystallised intelligence Jan 1, 1967 The 180 elementary abilities discovered by Guilford Jan 1, 1993 Carroll proposes the three-stratum model of cognitive ability Jan 1, 1995 Sternberg and Wagner design a test of practical intelligence