Cognition refers to mental processes such as thinking, knowing, remembering, problem solving, and decision making. There are different types and categories of cognition. Intelligence can be measured through achievement tests which measure what has been learned, and aptitude tests which predict future performance. While IQ tests aim to measure intelligence, they have limitations and do not capture all types of intelligence. Creativity involves divergent problem solving and can be influenced by factors like functional fixedness but is only moderately correlated with intelligence.