Mental rotation and the motor system: Embodiment head over heels

Abstract

We examined whether body parts attached to abstract stimuli automatically force embodiment in a mental rotation task. In Experiment 1, standard cube combinations reflecting a human pose were added with (1) body parts on anatomically possible locations, (2) body parts on anatomically impossible locations, (3) colored end cubes, and (4) simple end cubes. Participants (N=30) had to decide whether two simultaneously presented stimuli, rotated in the picture plane, were identical or not. They were fastest and made less errors in the possible-body condition, but were slowest and least accurate in the impossible-body condition. A second experiment (N=32) replicated the results and ruled out that the poor performance in the impossible-body condition was due to the specific stimulus material. The findings of both experiments suggest that body parts automatically trigger embodiment, even when it is counterproductive and dramatically impairs performance, as in the impossible-body condition. It can furthermore be concluded that body parts cannot be used flexibly for spatial orientation in mental rotation tasks, compared to colored end cubes. Thus, embodiment appears to be a strong and inflexible mechanism that may, under certain conditions, even impede performance.

Mental rotation and the human body: Children's inflexible use of embodiment mirrors that of adults

“…However, there is a recent example that first-graders, at least, can cope with quasi 3D stimuli in a mental rotation task if presented with cubes with surfaces coloured differently (L€ utke & Lange-K€ uttner, 2015). Therefore, quasi 3D stimuli were used in the current experiment to enhance comparability with the findings in adults (Kr€ uger, Amorim, et al, 2014). The test stimuli consisted of pictures of cube combinations, either pure or with body parts attached ( Figure 1).…”

“…Wilson, 2002) 1 is forced upon the mental transformation by a projection of the human body onto the stimulus material. The goal of this study was to test whether the effects of anatomically possible stimuli enhancing mental rotation and of anatomically impossible stimuli impeding it (see Kr€ uger, Amorim, et al, 2014) can also be obtained in children. This is of particular theoretical interest, as different developmental trajectories are conceivable: The effects of embodiment on imagery might increase or decrease (or even stay the same) across development.…”

“…To this end, the body parts were attached in a way that allowed for the successful projection of a human body (anatomically possible) or disallowed such a projection (anatomically impossible). Previous findings showed that the attachment of body parts led to specific embodiment effects in adults: Anatomically possible stimuli enhanced mental rotation performance, while anatomically impossible stimuli impeded the performance compared to the pure cube stimuli (Kr€ uger, Amorim, et al, 2014). In contrast to the embodiment effect of rotating hands mentally, there has been no data yet on these effects on children's mental rotation.…”

“…Therefore, we were looking for qualitative changes, that is, whether an effect of embodiment is already present in a specified age group. More specifically, we examined whether children show the benefits of a projection of the human body onto the anatomically possible stimuli and/or the inflexible processing of anatomically impossible stimuli, as reported previously for adults (e.g., Kr€ uger, Amorim, et al, 2014). A lack of such effects in children would strongly support the idea that motor and imagery functions become integrated with age, because the benefits of a projection of the human body onto the anatomically possible stimuli and the inflexible processing of anatomically impossible stimuli would have been acquired through development.…”

“…This allows the projection of a complete human body on the stimulus material (see Figure , middle column). However, when these replaced cubes do not allow for a projection of the human body because the body parts are placed in an anatomically incompatible way (see Figure , right column), the effect is reversed (Krüger, Amorim, & Ebersbach, ; for a replication of these findings, see Appendix A; see also Amorim et al ., ). There is a clear hierarchy comparing the effect of these three types of stimuli.…”