SNA All-Star: Frank Harary

Frank Harary became a math instructor at the University of Michigan in 1948 having journeyed from an interest in theoretical physics towards pure mathematics. As he was promoted through the ranks of professorship his research interest kept shifting and in addition to his position in the Department of Mathematics, Harary took on a research associate role in the Institute of Social Research in 1950 joining Leon Festinger and Doriwn Cartwright who had moved part of Kurt Lewin’s original research center to Michigan from MIT. 

An international authority in graph theory, Harary grew increasingly interested in applying graph theory to social relations and structural concepts. Together with Cartwright he authored a key paper on the uses of graph theory for expanding upon Heider’s theory of balance (Cartwright and Harary, 1956). Cartwright and Harary used graph theory to develop a generalization of Heider's theory of balance with the help of concepts from the mathematical theory of linear graphs. 

They translated Heider’s diagrams and language into graph theoretic terms and summarized them visually. They thus were able to make key alterations and extensions to balance theory - Heider's theory was originally intended to refer only to cognitive structures of an individual person while Harary and Cartwright proposed that the definition of balance may be used generally in describing configurations of many different sorts, such as communication networks, power systems, sociometric structures, systems of orientations, or perhaps neural networks - and thus contributed important early advances to the field of SNA. 

The use of graph theory for developing formal definitions for concepts such as cliques, centrality and balance resulted in significant early progress in SNA on both theoretical and methodological grounds.  

Entry is based on Prell "Social Network Analysis" and Cartwright and Harary "Structural balance: a generalization of Heider's theory"