A further study of the psychometric qualities of the Strange Stories-Revised across the three stages of aging.

Introduction: Happé's Strange Stories task was developed in 1994 to assess theory of mind, the ability to infer mental states in oneself and others. Since then, it has undergone revisions, translations, and adaptations. A modified version of the task, the Strange Stories-Revised (SS-R), previously showed satisfactory qualities in a study aiming at identifying psychometrically acceptable social cognitive measures.

Objective: The current study expands upon the psychometric evaluation study by examining the qualities of a short version of the SS-R in a sample of healthy adult subjects.

Methods: One hundred and eighteen healthy adults completed the task along with neurocognitive measures. Mean scores of the long and short versions were compared. Associations between ToM as measured by performance on this abbreviated version of the SS-R, and potential confounders were explored. Internal consistency, dimensionality of the short version, and performance comparisons across three stages of aging (18-34; 35-59; 60-85 years old) were investigated, and standard measurement error was calculated to improve precision and data interpretation.

Results: Reliability coefficients were comparable in the short and long versions. Principal component analysis showed that a one-factor structure best fits the data. Significant differences were observed in ToM performance across the three age groups, indicating a decline with time that was also captured by the long version, starting during midlife and increasing in significance with age.

Conclusion: The short version of the SS-R is a promising measure that can be profitably used in time-limited settings to assess theory of mind.