TY - JOUR
T1 - Grasp Point Selection, Perceptual Judgment and Object Symmetry
AU - Lederman, SJ
AU - Wing, Alan
PY - 2003/9/1
Y1 - 2003/9/1
N2 - Object symmetry is a visual attribute that may contribute to perceptual judgement and to action. We evaluated the effects of varying the physical symmetry of planar objects (presence versus absence) on both aspects. In Experiment 1, subjects estimated the magnitude of visually perceived symmetry of the objects. The results confirmed the influence of physical symmetry on perceived symmetry, and supported our binary categorisation of stimulus objects in terms of presence versus absence of physical symmetry. In Experiment 2, participants used a precision grip to grasp and stably lift the same planar objects varying in degree of symmetry. Choice of grasp points was unrestricted. Participants selected a grasp axis (between thumb and middle finger) that limited the perpendicular distance from CM (i.e., grasp-axis error) to just a few millimetres. Moreover, they took advantage of visual cues to object symmetry to better determine CM, thus reducing their grasp-axis error for symmetric (vs. asymmetric) objects by 31%. We interpret these findings in terms of user and object-geometry constraints on grasp-point selection.
AB - Object symmetry is a visual attribute that may contribute to perceptual judgement and to action. We evaluated the effects of varying the physical symmetry of planar objects (presence versus absence) on both aspects. In Experiment 1, subjects estimated the magnitude of visually perceived symmetry of the objects. The results confirmed the influence of physical symmetry on perceived symmetry, and supported our binary categorisation of stimulus objects in terms of presence versus absence of physical symmetry. In Experiment 2, participants used a precision grip to grasp and stably lift the same planar objects varying in degree of symmetry. Choice of grasp points was unrestricted. Participants selected a grasp axis (between thumb and middle finger) that limited the perpendicular distance from CM (i.e., grasp-axis error) to just a few millimetres. Moreover, they took advantage of visual cues to object symmetry to better determine CM, thus reducing their grasp-axis error for symmetric (vs. asymmetric) objects by 31%. We interpret these findings in terms of user and object-geometry constraints on grasp-point selection.
KW - grasp
KW - visually-guided action
KW - object symmetry
KW - perceived object symmetry
KW - grasp-axis orientation
UR - http://www.scopus.com/inward/record.url?scp=0141453304&partnerID=8YFLogxK
U2 - 10.1007/s00221-003-1522-5
DO - 10.1007/s00221-003-1522-5
M3 - Article
C2 - 12879179
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
SN - 1432-1106
VL - 152
SP - 156
EP - 165
JO - Experimental Brain Research
JF - Experimental Brain Research
ER -