Abstract
It is known that in mental-rotation tasks, subjects mentally transform the displayed material until it appears "upright" and then make a judgment. Here we evaluate, by using three typical mental rotation tasks with different degrees of embodiment, whether "upright" is coded to a gravitational or egocentric reference frame, or a combination of both. Observers stood erect or were whole-body tilted by 60°, with their left ear down. In either posture, they saw stimuli presented at different orientation angles in their frontal plane: in condition LETTER, they judged whether the stimuli were normal or mirror-reversed letters, in condition HAND whether they represented a left or a right hand, and in condition SCENE whether a weapon laid left or right in front of a displayed person. Data confirm that reaction times are modulated by stimulus orientation angle, and the modulation curve in LETTER and HAND differs from that in SCENE. More importantly, during 60° body tilt, the modulation curve shifted 12° away from the gravitational towards the egocentric vertical reference; this shift was comparable in all three conditions and independent of the degree of embodiment. We conclude that mental rotation in all conditions relied on a similar spatial reference, which seems to be a weighted average of the gravitational and the egocentric vertical, with a higher weight given to the former.
Original language | English |
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Journal | Human movement science |
Volume | 40 |
Issue number | April |
Pages (from-to) | 352-358 |
Number of pages | 7 |
ISSN | 0167-9457 |
DOIs | |
Publication status | Published - 04.2015 |
Research areas and keywords
- Adult
- Depth Perception
- Female
- Gravitation
- Human Body
- Humans
- Male
- Normal Distribution
- Orientation
- Photic Stimulation
- Posture
- Reaction Time
- Rotation
- Vision, Ocular
- Writing
- Young Adult