Intellectual functioning, as the term implies, refers to the individual’s intellectual capacity and is what we refer to when we discuss IQ scores. Although the IQ score is often discussed as a unitary concept, it is composed of a number of components that include verbal reasoning, visuomotor abilities, working memory and the speed and efficiency with which information is processed. Intelligence testing is important because it enables the neuropsychologist to determine what level of performance can be expected from the individual. For example, an individual with high performance on the intelligence test, but poor performance in terms of academics is clearly not functioning to the level that he or she is capable. The question then arises, what is preventing this individual from performing at a higher level? This question will hopefully be answered by the other components of the evaluation.