Experimental task
We employed a modified version of the MASC task, which assesses mentalizing performance using a set of videos depicting subsequent stages of social interactions between four human agents. The four agents spend an evening together, take part in various activities and interact in friendly, hostile, or romantic ways. The movie is interrupted at key timepoints by four-alternative-forced-choice questions about the currently ongoing social situation (e.g., “what is Michael feeling?”). The four response options represent four possible levels of mentalizing: overmentalizing, “normal” mentalizing, undermentalizing or no mentalizing. The “normal” mentalizing response is the answer that most healthy participants would give and is considered the “correct” answer to the question. Our version of the MASC task was structured as follows (Fig. Depiction of one trial of the experimental task, a modified version of the MASC experiment by Dziobek et al.