Abstract
Mental rotation is a spatial reasoning skill that has been widely studied and is predictive of general intelligence, creativity, and STEM performance. Most of the research on mental rotation has relied on a single category of stimuli that originates from the seminal article by Shepard and Metzler (1971). It is important to develop new categories of stimuli to allow for broader generalizability. For example, in the interest of developing training protocols to improve mental rotation, training on a broad range of stimuli can lead to more generalizable training effects. The current study validates a new set of mental rotation stimuli that are composed of three-dimensional (3D) spheres as opposed to the typical 3D cubes. Participants performed a mental rotation task, where they determined if two stimuli were the same or mirrored versions of the same object at varying degrees of angular disparity. One group of participants performed this task with 3D cube stimuli (n = 37) that have previously shown reliable effects of increasing response time (RT) and errors with increases in angle of disparity. Another group performed the same task with the sphere stimuli (n = 41). ANOVAs comparing stimuli showed no main effects for accuracy and RT, suggesting similar overall performance. In addition, as angular disparity increased, RT and errors increased for both stimulus types. There was an interaction between stimuli type and angle of disparity for accuracy due to a steeper slope for cube than sphere stimuli. However, this was not the case for RT. Therefore, sphere stimuli maintain higher accuracy as more rotation is required but perform similar to cubes in the amount of time needed to complete the rotation. Based on these results, we provide a new set of validated mental rotation stimuli that can help in studies looking for broader generalizability.