The 36-Item Yoni Task: Normative Data for the Clinical Assessment of Theory of Mind

Background: The evaluation of Theory of Mind (ToM) in the clinical setting remains limited due to the lack of valid instruments for a quick and reliable assessment. In this study, the psychometric properties of the Yoni-36 task were tested, and correction grids, equivalence scores, and normative data were computed. Methods: In total, 318 healthy subjects (169 females; mean age = 42.22 ± 18.11 years; mean education = 15.01 ± 3.43 years) were enrolled and administered the Yoni-36 task. Results: Statistical analysis showed good-to-high internal consistency, split-half reliability, and discrimination ability (especially for the second-order items) of the Yoni-36 task. Regression models highlighted the predictive role of age and education on second-order, affective, cognitive accuracy, and response time scores. Education influenced the first-order ToM response time score as well. Based on β values of the regressions, raw scores of the Yoni task were adjusted for sex, age, and education, and correction grids were computed. The equivalent scores indicated an accuracy index score < 0.69 and a response time index score < 0.83 as cut-off points for ToM competence. Normative data reported a mean accuracy and response time index score of 0.90 ± 0.11 and 0.91 ± 0.05 in the Italian population, respectively. Conclusions: The Yoni-36 proved to be a valid instrument for a quick and reliable ToM assessment, suitable to be included in neuropsychological batteries and to be used in routine clinical practice.