Psychometric evaluation and validation of the Serbian version of Reading the Mind in the Eyes test

Reading the Mind in the Eyes test (RMET) is one of the most popular and widely used measures of individual differences in Theory of Mind (ToM) capabilities. Despite demonstrating good validity in differentiating various clinical groups exhibiting ToM deficits from unimpaired controls, previous studies raised the question of the RMET's homogeneity, latent structure, and reliability. The aim of this study is to provide evidence on psychometric properties, latent structure, and validity of the newly adapted Serbian version of the RMET. In total, 260 participants (61.9% females) took part in the study. The sample consisted of both unimpaired controls (76.5%), and a clinical group of participants that are believed to demonstrate ToM deficits (23.5%), namely, persons diagnosed with schizophrenia and bipolar disorder (54.1% females). RMET has demonstrated fair psychometric properties (KMO=.723; alpha=.747; H1=.076; H5=.465), successfully differentiating between clinical group and control [F (1,254)=26.175, p <. 001, eta(2)(p) =.093], while typical gender differences in performance were found only in control group. Tests of several models based on the previous literature revealed that the affect-specific factors underlying performance on RMET demonstrate poor fit. The best fitting model obtained included reduced scale with a single-factor underlying the test's performance (TLI=.953, CFI=.958, RMSEA=.020). Based on the fit parameters we propose 18-item short-form of the Serbian version of RMET (KMO=.797; alpha=.728; H1=.129; H5=.677) for economic, reliable and valid measurement of ToM abilities.