Abstract abilities were studied in a sample of 34 individuals with severe TBI and a control group. The results indicate that TBI interferes with performance on tests requiring individuals to process information into new categories. There appears to be a dissociation between verbal abstract abilities and visual-perceptual abstract abilities. There is evidence that Goldstein and Sheerer's [1] postulate of a general‘abstract attitude’was at least partially correct. This attitude does not appear to be related to a general verbal ideational process, as dysphasic subjects were only deficient on a purely verbal abstract task.