The Short Interpersonal Reactions Inventory, Self-regulation and differentiation scales in an older Australian twin sample

An English translation of the Differentiation and Self-regulation extension scales has been used in conjunction with a reduced form of the Short Interpersonal Reactions Inventory (SIRI) in a sample of 2844 Australian twins aged over 50. Significant correlation was found between Type 1 (cancer-prone) and Type 2 (coronary heart disease prone), and between Self-regulation and Type 4 (healthy). The low correlations reported in other studies between the two alternative subscales of Type 4 are also observed. The Differentiation scales of Agitation and Inhibition were not found to significantly improve discrimination between Grossarth-Maticekʹs personality Type 1 and 2 subjects in this study