It is difficult to account for the real and easily measured differences in verbal competence. Differential psychologists investigate basic traits from which observed behavior is thought to be generated, but if thinking is viewed as a problem in information handling, research will more profitably focus on the relationship between behavior in handling problems of linguistic information processing and behavior on verbal aptitude tests. This will account for the way information processes vary between individuals. The recommended model of reading is based on a series of stages: decoding, active memory, sentence processing, and analysis using long-term memory. Differences in verbal competence have much to do with strictly mechanical components, particularly automatic structural processes such as decoding and short-term memory capacity, the ability to control attention, and the use of strategies, all of which are components of individual mental competence. The measures which would be expected to be important in information processing are roughly associated with general mental and verbal competence. (Tables and references are included.) (DF)