Psychological testing measures an individual's performance at a specific point in time. Psychological tests can't predict future or innate potential. Psychological testing is not a single test or even a single type of test. It encompasses a whole body of dozens of research-backed tests and procedures of assessing specific aspects of a person's psychological makeup.
Cognitive functions can be defined as cerebral activities that lead to knowledge, including all means and mechanisms of acquiring information. Cognitive functions encompass reasoning, memory, attention, and language and lead directly to the attainment of information and, thus, knowledge.