Assessment of visual field dependence: comparison between the mechanical 3D rod-and-frame test developed by Oltman in 1968 with a 2D computer-based version.

The identification of subject's perceptual style regarding multisensory integration is a central issue for spatial perception and sensorimotricity. In spatial orientation studies, the weighting of visual frame of reference (visual field dependence) is classically assessed by using verticality perception tasks, and especially the mechanical 3D rod-and-frame test (3D RFT). The validation of a 2D computer-based version of the RFT by virtue of its portability would facilitate the identification of modes of spatial referencing for the design and evaluation of sensory and motor rehabilitation programs. We question here whether the computerized 2D RFT yields frame effects similar (in amplitude, direction) and correlated to those induced by the mechanical 3D RFT. In both devices, 35 young and healthy males' subjects were seated and tasked with aligning a rod to the gravity vertical within a square frame that was tilted at 18 degrees . The results showed significantly larger rod deviations from the verticality in the 3D RFT. 3D and 2D RFT errors significantly correlated but shared a small amount of common variance (r<formula>;{2}</formula> = 0.35). In addition, left-right tilt asymmetry changes from one device to another. These results suggest that the mechanical 3D RFT for verticality perception remains a more robust test for identifying the subject's perceptual style.