The relationship between general intellectual ability and performance on ecologically valid executive tests in a severe brain injury sample.

Recent studies of brain injured and healthy individuals have provided empirical support for the theoretical proposition that executive function and general intelligence are closely associated by demonstrating that performance on tests of executive function is correlated with general intellectual ability (g). In the present investigation, the relationship between performance on the Wechsler Adult Intelligence Scale-III (WAIS-III), as a measure of g, and performance on recently developed ecological tests of executive function [i.e., Hayling and Brixton, Zoo Map and Key Search sub-tests from the Behavioral Assessment of the Dysexecutive Syndrome (BADS) battery], was examined in a sample of 118 severely brain injured individuals. The results indicated that (a) performance on tests of executive function share significant variance, and (b) a proportion of that shared variance is associated with performance on the WAIS-III. Correlations between conventional measures of executive function (i.e. Trails B and Controlled Oral Word Association) and WAIS-III were of comparable magnitude to the correlations between new, ecologically valid executive tests and WAIS-III. The results provide some support to the notion that tests of executive function measure non-specific intellectual functions, reminiscent of g.