A virtual environment for egocentric and allocentric mental transformations: a study on a non clinical population of adults with distinct levels of schizotypy

We benefited from the flexibility provided by virtual reality to enhance a classical paradigm on array and self mental rotations and related questions on a set of items. We used this paradigm to investigate how the Level of Schizotypy in nonclinical subjects might influence their behavior in egocentric and allocentric mental transformations. Three elements of novelty were introduced: (i) we separated the phases of mental transformation (Imagined Rotation Phase) and task performance (Task Phase), (ii) we measured the time required for Imagined Rotation Phase and Task Phase separately, and (iii) we cued self-rotations with a virtual human being (selfavatar) or an inanimate object (self-chair). Twenty-four nonclinical participants were categorized in low- and highschizotypal subjects (Low-S, High-S). A mixed-design analysis of variance showed that High-S were significantly faster than Low-S during the Imagined Rotation Phase (array and self-chair rotations) and during the Task Phase (self-chair). High-S were also faster in the self-chair than in the selfavatar rotation, supporting the existence of a dissociation between perspective changing and perspective taking in High-S. In line with the literature, we found that participant performances decreased with increasing angular difference between the initial and the imagined perspective.