We consider what separates this from psychology in general, who is identified with advances, and how it has been applied and to what ends.
David Berliner associates the founding of the field with the 1892 founding of the American Psychological Association in his centennial history of educational psychology. pdf 
William James writes in his 1899 textbook, Talks to Teachers on Psychology, "Psychology is a science, and teaching is an art; and sciences never generate arts directly out of themselves. An intermediate inventive mind must make that application, by using its originality"
Alfred Binet began his scientific study of education in response to a law making school mandatory. Appointed to the Commission for the Retarded, the question became "What should be the test given to children thought to possibly have learning disabilities, that might place them in a special classroom?"
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Some historical figures and perspectives to be considered as starting points in this enquiry into application of scientific methods. wikipedia
See also Psychology as Popular Science