The Influence of the Design of Mental Rotation Trials on Performance Differences Between Sexes

The spatial ability of mental rotation describes the cognitive ability to rotate objects or images in the mind. Sex differences in mental rotation performance are one of the largest in cognitive psychology and of great interest due to the relationship of spatial abilities to STEM fields. Men outperform women by up to one standard deviation in psychometric mental rotation tests, where compared with one target, two out of four alternatives are rotated and the other two are mirrored or structurally different. However, there is no or only a much smaller sex difference for chronometric mental rotation tests, where two objects are presented which are either rotated or mirrored to each other. As both tests are supposed to measure the same ability, we suspect some features of the tests themselves to affect sex differences in performance. By comparing the trial features of existing tests and recent adaptions, we identified the number of possible answer alternatives and whether they are presented as pairwise mirrored as possible reasons. To evaluate the effect of each of these factors and their interaction on sex differences in performance, we plan to test 860 participants based on suggested participant numbers for appropriate power (Brysbaert, 2019) and power simulations. We target participants without specific STEM affiliation and without specific experience with mental rotation, as these have shown the largest sex differences. In an online experiment implemented with OpenSesame, participants will solve four blocks of mental rotation trials with two or eight alternatives, which are either pairwise mirrored or not. Each block will have a time limit of three minutes. The average number of correct answers will be analyzed for each block using linear mixed models. We aim to provide insight how test features influence sex differences in the mental rotation performance. Current theories are mostly related to the effect of biological or social factors on mental rotation ability. The question remains why only one test design provokes these factors to manifest in performance differences between sexes. Uncovering the underlying mechanisms could help us pinpoint the reason for sex differences in the broad psychometric test performance and whether and how much they are related to actual mental rotation ability. If part of the reason for sex differences is unrelated to mental rotation ability, this could also be transferred to other tests and other cognitive abilities.

This is a preregistration of the article: Jost, L., & Jansen, P. (2023). The influence of the design of mental rotation trials on performance and possible differences between sexes: A theoretical review and experimental investigation. Quarterly Journal of Experimental Psychology, 0(0). https://doi.org/10.1177/17470218231200127