Reasoning, problem solving, and decision-making represent different but overlapping aspects of human intelligence. The researchers following the cognitive psychological approach to the study of reasoning study the responses of a small number of participants to logical tasks such as syllogisms or formal logic tasks. The theories dominating psychological theorizing about reasoning are: mental rules and mental models. Both theories were first applied to the study of deductive reasoning tasks such as syllogisms and then applied to a broader range of reasoning tasks. Human reasoning occurs at different levels of awareness. Most cognitive scientists distinguish between tacit and intentional (or explicit) reasoning processes. One of the important controversies about reasoning abilities is the extent to which individual differences in reasoning abilities overlap with individual differences in working memory capacity. Traditionally, tests such as the Cognitive Abilities Test (CogAT) or the SAT have been used to provide a measure of cognitive development.