The influence of object complexity and rotation angle on eye movements during mental rotation

The scientific objective of the study was to identify factors modifying the eye movements observed during the performance of mental rotation tasks. On the one hand, differences were sought in indicators concerning eye movements between the phases of the perception of an object in the original and rotated positions; on the other hand, the study tested the influence of object complexity on the strength of similarity between perception and visualization in terms of the times of eye fixation in corresponding regions of interest. The results showed longer mean fixation times as well as a lower number and frequency of eye fixations when visualizing objects compared to viewing them. It can therefore be concluded that mental images required longer and deeper data processing than viewed objects did. The similarity of perception and visualization in terms of visual fixation times in corresponding regions of interest was stronger for simple objects than for complex ones. Moreover, it was demonstrated that for larger rotation angles the number of fixations was higher and their frequency was lower compared to smaller angles, which suggests an increase in perceived task difficulty and an increase in cognitive engagement with the increase in rotation angle.