These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Does gravity play an essential role in the asymmetrical visual perception of vertical and horizontal line length?
    Author: Lipshits M, McIntyre J, Zaoui M, Gurfinkel V, Berthoz A.
    Journal: Acta Astronaut; 2001; 49(3-10):123-30. PubMed ID: 11669100.
    Abstract:
    The eye perceives the length of vertical and horizontal lines with an inherent asymmetry. A vertical line having the same length as a horizontal one is usually perceived to be longer. In this experimental investigation we tested the hypothesis that gravity has a direct role in producing the observed perceptual asymmetry. To this end we performed experiments in weightlessness during long-orbital space flights onboard the MIR station. Subjects performed a psychophysical task in which the length of a visually-presented vertical line was adjusted to match the length of a horizontal reference. On Earth, almost all subjects produce errors in adjusting the length of the vertical line, consistently under-estimating the length of the horizontal reference. The asymmetry of perception of the line lengths persisted in weightlessness. From these results we conclude that the phenomena of asymmetry of perception of the lengths of vertical and horizontal lines is not dependent on gravity, but is instead defined by properties of the system of internal representation. Grant numbers: 99-04-48450.
    [Abstract] [Full Text] [Related] [New Search]