a1 University of Ulster, Coleraine, Northern Ireland
a2 University of Buckingham, England
Children's intelligence increased in the United States by approxi-mately 3 IQ points per decade over the period 1932–78. New evidence shows that these increases have been sustained during the last 20 years. Two recent studies indicate that the rates of increase for 1972–89 and 1978–89 were 3·3 and 3·5 IQ points per decade respectively.
(Received July 30 1992)