Fixation locations when grasping partly occluded objects

Denise D. J. de Grave, Constanze Hesse, Anne-Marie Brouwer, Volker H. Franz

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

When grasping an object, subjects tend to look at the contact positions of the digits (A. M. Brouwer, V. H. Franz, D. Kerzel, & K. R. Gegenfurtner, 2005; R. S. Johansson, G. Westling, A. Bäckström, & J. R. Flanagan, 2001). However, these contact positions are not always visible due to occlusion. Subjects might look at occluded parts to determine the location of the contact positions based on extrapolated information. On the other hand, subjects might avoid looking at occluded parts since no object information can be gathered there. To find out where subjects fixate when grasping occluded objects, we let them grasp flat shapes with the index finger and thumb at predefined contact positions. Either the contact position of the thumb or the finger or both was occluded. In a control condition, a part of the object that does not involve the contact positions was occluded. The results showed that subjects did look at occluded object parts, suggesting that they used extrapolated object information for grasping. Additionally, they preferred to look in the direction of the index finger. When the contact position of the index finger was occluded, this tendency was inhibited. Thus, an occluder does not prevent fixations on occluded object parts, but it does affect fixation locations especially in conditions where the preferred fixation location is occluded.

Original languageEnglish
Article number5
Number of pages11
JournalJournal of Vision
Volume8
Issue number7
DOIs
Publication statusPublished - 19 May 2008

Fingerprint

Fingers
Thumb

Keywords

  • fixations
  • saccades
  • eye movements
  • occlusion
  • grasping

Cite this

Fixation locations when grasping partly occluded objects. / de Grave, Denise D. J.; Hesse, Constanze; Brouwer, Anne-Marie; Franz, Volker H.

In: Journal of Vision, Vol. 8, No. 7, 5, 19.05.2008.

Research output: Contribution to journalArticle

de Grave, Denise D. J. ; Hesse, Constanze ; Brouwer, Anne-Marie ; Franz, Volker H. / Fixation locations when grasping partly occluded objects. In: Journal of Vision. 2008 ; Vol. 8, No. 7.
@article{f2222f6ee5d54a20a62d424478d3fe97,
title = "Fixation locations when grasping partly occluded objects",
abstract = "When grasping an object, subjects tend to look at the contact positions of the digits (A. M. Brouwer, V. H. Franz, D. Kerzel, & K. R. Gegenfurtner, 2005; R. S. Johansson, G. Westling, A. B{\"a}ckstr{\"o}m, & J. R. Flanagan, 2001). However, these contact positions are not always visible due to occlusion. Subjects might look at occluded parts to determine the location of the contact positions based on extrapolated information. On the other hand, subjects might avoid looking at occluded parts since no object information can be gathered there. To find out where subjects fixate when grasping occluded objects, we let them grasp flat shapes with the index finger and thumb at predefined contact positions. Either the contact position of the thumb or the finger or both was occluded. In a control condition, a part of the object that does not involve the contact positions was occluded. The results showed that subjects did look at occluded object parts, suggesting that they used extrapolated object information for grasping. Additionally, they preferred to look in the direction of the index finger. When the contact position of the index finger was occluded, this tendency was inhibited. Thus, an occluder does not prevent fixations on occluded object parts, but it does affect fixation locations especially in conditions where the preferred fixation location is occluded.",
keywords = "fixations, saccades, eye movements, occlusion, grasping",
author = "{de Grave}, {Denise D. J.} and Constanze Hesse and Anne-Marie Brouwer and Franz, {Volker H.}",
year = "2008",
month = "5",
day = "19",
doi = "10.1167/8.7.5",
language = "English",
volume = "8",
journal = "Journal of Vision",
issn = "1534-7362",
publisher = "Association for Research in Vision and Ophthalmology Inc.",
number = "7",

}

TY - JOUR

T1 - Fixation locations when grasping partly occluded objects

AU - de Grave, Denise D. J.

AU - Hesse, Constanze

AU - Brouwer, Anne-Marie

AU - Franz, Volker H.

PY - 2008/5/19

Y1 - 2008/5/19

N2 - When grasping an object, subjects tend to look at the contact positions of the digits (A. M. Brouwer, V. H. Franz, D. Kerzel, & K. R. Gegenfurtner, 2005; R. S. Johansson, G. Westling, A. Bäckström, & J. R. Flanagan, 2001). However, these contact positions are not always visible due to occlusion. Subjects might look at occluded parts to determine the location of the contact positions based on extrapolated information. On the other hand, subjects might avoid looking at occluded parts since no object information can be gathered there. To find out where subjects fixate when grasping occluded objects, we let them grasp flat shapes with the index finger and thumb at predefined contact positions. Either the contact position of the thumb or the finger or both was occluded. In a control condition, a part of the object that does not involve the contact positions was occluded. The results showed that subjects did look at occluded object parts, suggesting that they used extrapolated object information for grasping. Additionally, they preferred to look in the direction of the index finger. When the contact position of the index finger was occluded, this tendency was inhibited. Thus, an occluder does not prevent fixations on occluded object parts, but it does affect fixation locations especially in conditions where the preferred fixation location is occluded.

AB - When grasping an object, subjects tend to look at the contact positions of the digits (A. M. Brouwer, V. H. Franz, D. Kerzel, & K. R. Gegenfurtner, 2005; R. S. Johansson, G. Westling, A. Bäckström, & J. R. Flanagan, 2001). However, these contact positions are not always visible due to occlusion. Subjects might look at occluded parts to determine the location of the contact positions based on extrapolated information. On the other hand, subjects might avoid looking at occluded parts since no object information can be gathered there. To find out where subjects fixate when grasping occluded objects, we let them grasp flat shapes with the index finger and thumb at predefined contact positions. Either the contact position of the thumb or the finger or both was occluded. In a control condition, a part of the object that does not involve the contact positions was occluded. The results showed that subjects did look at occluded object parts, suggesting that they used extrapolated object information for grasping. Additionally, they preferred to look in the direction of the index finger. When the contact position of the index finger was occluded, this tendency was inhibited. Thus, an occluder does not prevent fixations on occluded object parts, but it does affect fixation locations especially in conditions where the preferred fixation location is occluded.

KW - fixations

KW - saccades

KW - eye movements

KW - occlusion

KW - grasping

U2 - 10.1167/8.7.5

DO - 10.1167/8.7.5

M3 - Article

VL - 8

JO - Journal of Vision

JF - Journal of Vision

SN - 1534-7362

IS - 7

M1 - 5

ER -