American psychologist, one of the first specialists in experimental psychology in the United States, the first professor of psychology. The founder of testing methods, the author of a number of psychological tests (including a test for assessing the intelligence of college students), one of the first specialists in psychometry and psychodiagnostics. It was thanks to Cattell that the term “test” acquired the psychological meaning that is attached to it today. In 1890, Cattell’s article “Mental Tests and Measurements” was published in the journal “Mind”, where the practical use of psychometric methods was first scientifically substantiated. From the beginning of his career, Cattell devoted his work to making psychology a respected field of scientific inquiry, like the traditional natural sciences, chemistry, and physics. In this case, too, the statistical approach—the application of a series of tests to a large number of individuals—was put forward by him as a means of transforming psychology into an exact science. Another important contribution of Cattell to psychological science was the results of his experiments on the study of attention span and reading skills: the volume of attention fluctuates within 5 objects. Cattell founded the American Psychological Corporation, the first publishing firm specializing in the production of tests.