More mental rotation time does not imply more mental effort: Pupillary diameters do not change with angular distance

The ability to mentally rotate objects in space is a fundamental cognitive capacity. Previous studies showed that the time image of figure match another increases progressively with angular disparity. It remains unclear whether this increase response disparity could reflect increased processing operations or more effort instead sustained use ‘rotate’ mechanism without change workload. We collected times as well pupillary responses index workload and activity brainstem’s locus coeruleus, from sample 38 young adults performing chronometric mental rotations task. results expected but no pupil diameters between 60, 120, 180 degrees rotation, suggesting significant changes arousal levels when rotating figures near far. This indicates during rotation load on resources constant irrespective distance.