Abstract
Heider (1958), in his “balance theory”, defined the states of balance or imbalance in cognitive human relationships, but he did not discuss why the cognitive relationships were stable or unstable. We point out that both balance theory and eigen-decomposition algorithm hold the functional isomorphism based on an information compression process. Although it is difficult to apply eigen-decomposition to the interpersonal relational matrix because the relationships are asymmetric, the difficulty is overcome by Hermitian Form Model (HFM), which is a kind of Asymmetrical Multi-dimensional Scaling. By using this technique to the real socio-matrix, we have found that the contributed ratio of the first-eigenvalue in the time series increases. This result means that each member in the groups changes its relationship such that its structure is clearer. This change is the result of reflection of information compression on cognitive relationships of each member.
