Markus Krüger

Mental rotation and the motor system: embodiment head over heels.

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.

Verknüpfung von Vorstellung und Motorik in der Entwicklung

Zusammenfassung. In einem Reaktionszeitexperiment zur mentalen Rotation von Handen, an dem 138 Kindergartenkinder, 82 Grundschuler (2. Klassenstufe) und 82 Erwachsene teilnahmen, konnte ein Einfluss der motorischen Einschrankung von Handbewegungen auf die Vorstellung nachgewiesen werden. Dieser Motoreffekt war jedoch nicht in allen Altersgruppen und Bedingungen zu beobachten. Es konnte auch nicht bestatigt werden, dass er bei jungeren Kindern generell starker ausgepragt ist als bei alteren Kindern und Erwachsenen. Dafur gab es Hinweise darauf, dass die Bedingungen, unter denen ein Motoreffekt auftritt, systematisch mit dem Alter variieren. Insbesondere war bei Kindergartenkindern ein Motoreffekt nur dann zu beobachten, wenn die eigene Handstellung mit der Perspektive auf die prasentierten Hande korrespondierte.

Let’s twist again! Embodiment effects in spatial judgments on human figures rotated along a vertical axis

ABSTRACT We investigated whether individuals used mental rotation and embodiment for arm laterality judgments of human figures that were stepwise rotated from back view to front view along a vertical axis. In Experiment 1, figures’ heads were always shown in profile, while only the bodies were rotated. Judgments were faster and more correct when figures were presented in back view compared to front view, but the relation between reaction times (RTs) and rotation angles was not strictly linear. In addition, judgments on figures in anatomically possible postures were better than on figures in impossible postures. In Experiment 2, figures’ heads were turned together with their body. RTs and rotation angles were linearly related. Results suggest that individuals use both mental rotation and a more direct matching between their own body and that of the figures, when making arm laterality judgments of human figures that are rotated along a vertical axis.

Towards a new method for bridging the gap between “smart” infants and “dumb” preschoolers

Based on violation-of-expectation (VoE) paradigms, amazing cognitive competencies have been demonstrated in young infants, which could not be shown in toddlers or even preschoolers. This divergence might as much be caused by different research methods as by discontinuities in development. As looking-time measures are not readily applicable to older children, we suggest a new method that is suitable for children from two years of age onwards. In an empirical examination of this method, 26 children aged 2–7 years learned by trial and error to always find a target picture among a pair of pictures. Each target picture was an impossible version of the non-target picture. After reaching a learning criterion, children had to generalize the learned concept to pictures belonging to a different category. Results showed that even the youngest participants reached the learning criterion and were able to apply what they had learned to another category.

Adults’ Sex Difference in a Dynamic Mental Rotation Task

With the Mental Rotation Test (MRT), large and reliable sex differences are found. Used with children younger than about 9 or 10 years, MRT performance is at chance level. Simpler tasks used with younger children have revealed inconclusive results. Moore and Johnson (2008, 2011) observed sex differences in infants using a habituation task with 3D cube figures rotating back and forth in depth through a 240° angle. Thereafter, female infants treated similarly the original figure and a mirror-image cube figure presented revolving through the previously unseen 120° angle, whereas male infants behaved as if they recognized the familiar object. In the present study, 256 adults participated in the MRT as well as in a modified two-alternative forced-choice dynamic version of the infants’ task. Sex differences were present for both tasks. More importantly, there was a positive correlation in performance across both tasks for both women and men. Since the new task turned out to be simpler, it might be suitable also for children. We present the first, although indirect, evidence that the sex effects reported by Moore and Johnson might indeed reflect early sex differences in mental rotation.

Which object is about to fall? Development of young children’s intuitive knowledge about physical support relations as assessed in an active search task

ABSTRACT Previous studies measuring looking-time suggested that already infants possess intuitive knowledge about physical support. The aim of the present study was to investigate whether children were able to apply this knowledge in an active search task. Two- to five-year-olds (N = 105) were presented with pairs of identical blocks positioned on the left- and right-hand side of an elevated platform with only one of the blocks sufficiently supported. At test, one of the blocks fell into one of two chutes adjacent to the platform out of children’s view. Children’s task was to retrieve the block they thought had fallen. Results revealed that while children aged 3 years or older searched reliably in the correct chute with symmetrically-shaped blocks, only 4- and 5-year-olds did so with asymmetrical blocks. Thus, intuitions about support do not appear to become accessible in action before children can use them to make verbal predictions.

Theory of Mind and the Video Deficit Effect: Video Presentation Impairs Children’s Encoding and Understanding of False Belief

ABSTRACT The video deficit effect (VDE) has been demonstrated in several studies on word learning, self-recognition, and imitation: Younger children (up to 3 years old) solved tasks more easily in a direct interaction with an examiner than when instructed by video (Anderson & Pempek, 2005). Older children might also be susceptible to a VDE, especially with more complex tasks; however, evidence is sparse. Furthermore, to what extent preschoolers’ understanding of others’ mental states (theory of mind) is impaired by video presentations has not been tested. We tested 174 children of 4 and 5 years of age in a traditional change of location task for false belief understanding (cf. Baron-Cohen, Leslie, & Frith, 1985). Children were presented with the original story, enacted by adult actors, in either a video or a live demonstration. Children watched the events in 2 live conditions, either through a 1-way mirror or directly. Our results indicate a significant VDE for 4- and 5-year-old children regarding the encoding and solution of the false belief task, respectively.