Using a modified Posner "encoding function" methodology, group differences in semantic encoding speed were assessed under conditions in which subjects encoded pictures of common objects to determine physical identity matches, name identity matches, and superordinate identity matches. Results of primary interest revealed group differences in basic…

Administered a complex reaction time task to 47 learning-disabled and 41 control children. The preparatory interval between a warning and act light was manipulated for length and regularity. Results indicated that the inability to sustain attention over time, rather than momentary inattentiveness, distinguished the two groups. (Author)

A comparison of test results on the Visual Discrimination Test was made between a group of 22 reading disabled children and 22 children who were reading on or above grade level. Both groups were of average or above-average intelligence and the two groups were matched for age and sex. The mean age was 10 years and 3 months and all the reading…

Two studies with 658 white and 353 African-American elementary school children performing reaction time tasks are offered in support of Spearman's hypothesis about the relative size of the mean African-American-white differences on mental tests as a function of the tests' loadings on psychometric "g." (SLD)