September 2021
Volume 21, Issue 9
Open Access
Vision Sciences Society Annual Meeting Abstract  |   September 2021
Bimanual grasping adheres to Weber’s law
Author Affiliations
  • Martin Giesel
    University of Aberdeen
  • Róisín Elaine Harrison
    University of Aberdeen
  • Thomas Schenk
    LMU Munich
  • Constanze Hesse
    University of Aberdeen
Journal of Vision September 2021, Vol.21, 2512. doi:
  • Views
  • Share
  • Tools
    • Alerts
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      Martin Giesel, Róisín Elaine Harrison, Thomas Schenk, Constanze Hesse; Bimanual grasping adheres to Weber’s law. Journal of Vision 2021;21(9):2512.

      Download citation file:

      © ARVO (1962-2015); The Authors (2016-present)

  • Supplements

While Weber’s law seems to hold true for most stimulus attributes and sensory modalities, so far it has consistently been found that it is violated in grasping. One suggested explanation for the absence of Weber’s law in grasping is that biomechanical constraints of the hand may mask its effect. However, Ganel et al. (Sci Rep 7, 6467, 2017) reported that Weber’s law is also violated in bimanual grasping. Here, we revisited the question of whether the elimination of biomechanical constraints results in grasping behaviour consistent with Weber’s law by using a modified and extended version of the bimanual study by Ganel et al. (2017). As stimuli, we used cubes with different side length (16, 24, 32, and 40 cm). Participants (N=20) performed two different tasks: bimanual grasping (action task) and bimanual estimation (perceptual task). In the action task, participants were asked to grasp and lift a cube with both hands. In the perceptual task, they were asked to indicate the size of a cube with their hands as accurately as possible. For each of the two tasks, there were two different conditions. In the “central” conditions, the distance between the start positions of the hands and the edges of the cubes increased with cube size, whereas in the “side” conditions, this distance remained constant. All tasks were performed visually open-loop. JNDs were estimated using the standard deviations of the maximum-hand apertures in the two tasks, respectively. We found adherence to Weber’s law in both bimanual estimation and grasping and independent of the hands’ start positions. These results are in direct conflict with those reported by Ganel et al. (2017). We discuss possible explanations for the divergent findings and encourage further research to establish whether or not actions still violate Weber’s law when biomechanical constraints are removed.


This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.