Realistic Stimuli Reveal Selective Effects of Motor Expertise During a Mental Body Rotation Task.

To investigate the effects of stimulus features on the implementation of motor expertise in body rotations during a mental body rotation task, 2 experiments were conducted. In Experiment 1, we investigated the mental rotation abilities in 27 male participants: 14 experts in real body rotations (national level gymnasts) and 13 nonexperts (national handball players). The mental rotation task used left-right judgments and involved 3 types of stimuli: images of a stick figure person, images of line drawings of the human body, and photographs of real male persons. In Experiment 2, 10 experts and 11 nonexperts performed a mental body rotation task on the same stimuli as in Experiment 1 using this time a same-different judgment. Results showed that stimulus features had a significant effect on the mental rotation of the participants because the more realistic stimuli resulted in shorter response times. Furthermore, experts outperformed nonexperts when the stimuli were presented in unfamiliar orientations (180* rotation). However, this pattern was significant only during the mental rotation task of photographs with left- right judgments, suggesting that stick figure person and line drawings of the human body did not differentiate experts and nonexperts. In conclusion, results suggest the existence of optimal stimulus features to elicit optimal embodiment and allow revealing selective effects of motor expertise in body rotations.