Block-design performance as a function of hue and race

The block-design subtest of the WISC was presented in two forms, the standard red/white and an alternative blue/yellow, to two groups of fourth- and fifth-grade children. Twenty black children and 20 white children performed the red/white task with no significant differences between their scores. Another 20 black and 20 white children performed the blue/yellow task showing a significant interracial difference. Within the group of black children there was also a significant difference between the red/white design scores and the blue/yellow design scores. It is proposed that genetically determined differences in the pigmentation of the fundus oculi account for these results.