The effects of movement direction and hemispace on estimates of distance traveled.
OBJECTIVE
The degree of attention directed to a stimulus and the presence of anisometric representations can alter the perception of the magnitude of a stimulus. We wanted to learn if normal right-handed subjects' estimates of distance traveled are influenced by the right-left direction or hemispace of movements.


METHODS
We had blindfolded participants estimate the distance their arm was moved in a rightward or leftward direction, in right and left hemispace. Since we wanted subjects to estimate the distance traveled rather than compute the distance between the start and finish points, the subjects' arms were passively moved in sinusoidal trajectories at a constant speed.


RESULTS
Subjects estimated leftward movements as longer than rightward movements, but there was no effect of hemispace. COMMENTS/CONCLUSIONS: People often attend more to novel than routine conditions and therefore participants might have overestimated the distance associated with leftward versus rightward movement because right-handed people more frequently move their right hand in a rightward direction and learn to read and write using rightward movements. Thus, leftward movements might be more novel and more attended than rightward movements and this enhanced directional attention might have influenced estimates of magnitude (distance).
Foster
Paul S
PS
Department of Neurology, University of Florida College of Medicine, and Malcom Randall Veterans Affairs Medical Center, Gainesville 32610-0236, USA. paul.foster@neurology.ufl.edu
Crucian
Gregory P
GP
Drago
Valeria
V
Burks
David W
DW
Mielke
Jeannine
J
Shenal
Brian V
BV
Rhodes
Robert D
RD
Grande
Laura J
LJ
Womack
Kyle
K
Riesta
Alonso
A
Heilman
Kenneth M
KM
D000368:Aged; D001288:Attention / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007699:Kinesthesis / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009039:Motion Perception / Q000502:physiology*; D012016:Reference Values; D013028:Space Perception / Q000502:physiology*