A person's performance is then compared with the average score for a particular age. The Stanford Binet was originally such a test. Includes anatomy, physiology, cytology, evolution, genetics, etc. Similarities are observed and, through inductive reasoning, a generalization results.
Negative correlation reflects consistency but inversion of relationships.
Always the first and simplest stage of a science. Developmental psychology, measurement and learning are the major subfields. G. S. Hall and Thorndike are the major founders. Nothing which has not been put in can be factored out. Behavior is predicted from what is known about stimulus and organismic variables.