STUDIES IN THE ACCURACY OF MOVEMENT. I. THE BISECTION AND DUPLICATION OF LINEAR EXTENS IN THE HORIZONTAL SAGITTAL PLANE.
Abstract
An attempt was made to determine the accuracy of simple linear movements in a horizontal plane parallel to the sagittal section. Subjects (10 in Experiment 11 in Experiment 2) sampled a given extent of linear movement by moving a rider back and forth on a track, and then attempted to bisect that extent (Experiment 1) or to duplicate it (Experiment 2). Distances ranged from 6 to 24 cm. in the first experiment, 4 to 18 cm. in the second. The results, expressed both as Mean Average Error (absolute deviations from the external standard), and as Mean Constant Error, indicate that: (1) proportional accuracy is greater for the duplication tasks than for bisection; (2) the proportional accuracy of duplicating sampled extents is considerably greater for the longer distances studied (8, 12, and 18 cm.) than for the shortest distance (4 cm.), the Mean Constant Error indicating a zero-order bias for the two longest distances and a rather large positive bias (approximately 11%) for the 4 cm. extent; (3) accuracy of bisecting sampled distances does not improve with increase in distance for the values studied (Mean AE remains at approximately 18%, Mean CE at about 15%), most of the error being due to a large and persistent positive bias (over-setting); (4) in this study no general superiority was found for settings made toward the subject or away from him. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1949
- Accession Number
- AD0640040
Entities
People
- A. L. Davidson
- D. B. Devoe
- S. D. S. Spragg
Organizations
- University of Rochester