Developing an Italian Adaptation of the Interpersonal Sensitivities Circumplex (ISC-IT) Using Ant Colony Optimization.

The Interpersonal Sensitivities Circumplex (ISC) measures individual differences in the sensitivity to interpersonal behaviors, organized along the dimensions of agency (e.g., sensitivity to others' assertive behavior) and communion (e.g., sensitivity to others' warm behavior). The present study aimed at validating a 40-item Italian adaptation of the ISC using methods that advance previous approaches to developing circumplex measures. Specifically, we (a) applied ant colony optimization, a well-performing technique to identify optimal items, (b) employed an item-level circumplex model to avoid limitations associated with item parceling, and (c) evaluated model fit using the dynamic fit index, which allows for a more rigorous assessment of theoretical structure. In two samples of the Italian general population (N = 401 and N = 301), the ISC-IT demonstrated sound psychometric properties, including acceptable model fit and internal consistency, and plausible associations with external variables. Using the ISC-IT, we replicated key findings from previous research, including that individuals are most sensitive to interpersonal behaviors that are opposite to their own, and that interpersonal sensitivities have both general and specific associations with maladaptive personality traits. This work contributes to the theoretical literature on interpersonal sensitivities and showcases contemporary test construction and validation techniques in developing circumplex measures.