Important to indentify a stable and reliable correlation between the task and the tests. Computer systems must be used by a wide variety of people in a mostly cognitive activity. HCI is concerned with the acquisition, manipulation and expression of abstract symbols which signify something else. HCI involves information processing. The user of the system must evaluate information based on the cognitive processing of external symbols systems.
Cognitive abilities are relatively stable and change very slowly.
Cooper and Mumaw's review of research on spatial ability concludes that the spatial aptitude literature is quite clear in showing that a broadly defined spatial factor exists independently of verbal and quantitative factors. Evidence shows holistic and serialistic learning styles, though an individual may utilize both. Differences in cognitive abilities can be measured between individuals, but it is hard to judge exactly what the difference is. A promising approach seems to be to identify the components of complex tasks and the cognitive abilities which are required to perform them. In this paper, he separates personality from cognition.