There has been a debate between N. J. Mackintosh and the first author of this paper on whether the sex difference on the Progressive Matrices is zero or, at most, 1–2 IQ points in favour of either sex, as maintained by Mackintosh, or whether from the age of 15 years onwards males obtain higher average scores than females by more than 2 IQ points, as maintained by Lynn. New data relevant to this controversy are presented from Hong Kong consisting of sex differences on the standardization sample of the Advanced Progressive Matrices on 15- to 18-year-olds. The results are that males obtained a higher mean score than females of 1·6 raw score points, equivalent to an advantage of 3·2 or 4·1 IQ points, according to two alternative methods of calculation. The results provide further confirmation that in later adolescence and among adults, males obtain significantly higher mean IQs on the Progressive Matrices than females.

Gabriel died on Tuesday 27 August 2002 in his 91st year. He had been a very committed member of the Editorial Board since January 1991 and he continued to review papers for the Journal with the same degree of impartiality and care until a week before he died.