Pupillometry as a measure of cognitive load in mental rotation tasks with abstract and embodied figures.

We investigated sex differences in behavioral performance and cognitive load in chronometric mental rotation tasks with abstract and embodied figures. Eighty participants (44 females and 36 males) completed 126 items, which included cube figures, body postures, and human figures, which were all comparable in shape and color. Reaction time, accuracy, and cognitive load, measured by changes in pupil dilation, were analyzed. As a function of angular disparity, participants showed shorter reaction times and higher accuracy rates for embodied stimuli than cube figures. Changes in pupil dilation showed a similar pattern, indicating that mental rotation of embodied figures caused less cognitive load to solve the task. No sex differences appeared in any of the measurements.