There are literally hundreds of psychological tests in existence. The best known among these are several tests of intelligence yielding the IQ score (the Stanford-Binet, and the Weschler tests). These and other similar tests are commonly used to classify people into mentally retarded, learning disabled, normal and gifted categories for school purposes.
Another well known set of tests are the Rorschach Ink Blot Test, and the Minnesota Multiphasic Personality Inventory (MMPI), which are examples of two very different sorts of personality tests. The Rorschach test involves making sense out of people’s spontaneous verbal responses to ambiguous ink blot pictures. The MMPI, in contrast, involves making sense out of a persons’ response to a large true or false answer questionnaire. The Rorschach test is ‘projective’ in that it is designed to make clear exactly how the test subject goes about making sense out of (projecting meaning onto) the ink blots. The MMPI is ‘objective’ in that conclusions drawn from it are based on rigorous scientific studies of how thousands of people have responded to the same set of true or false questions.
The field of Neuropsychology exists to assess the relationships between brain and behavior, especially when the brain is damaged. Neuropsychologists use specialized tests that measure memory, learning, attention, intelligence, concentration, etc. to demonstrate that brain damage has indeed occurred even when that damage may be too slight and mild to have resulted in something visible on an MRI, CT or X-ray scan.