Input (grade 5): The earliest expressions of the basic concepts were by R.A. Fisher in 1930, J. B. S. Haldane in 1955, but it was W. D. Hamilton who truly formalized the concept, in works published in 1963 andâ "most importantlyâ" in 1964.
Output (grade 2): The first to write about the concept were by R.A. Fisher in 1930, and J.B.S. Haldane in 1955, but it was W.D. Hamilton who truly formalized the concept.