Discrimination of Visual Linear Velocities |
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| Authors: | Charles H Shea Cheryl Northam |
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| Institution: | 1. Department of Health and Physical Education , Texas A&2. M University , USA |
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| Abstract: | Abstract The purpose of the present study was to determine velocity discrimination characteristics of subjects in a difference threshold paradigm. After recruitment, 180 male and female subjects were randomly assigned to 1 of 6 groups differentiated by the length of the stimulus runway and the subjects' orientation to the stimulus. Stimulus velocities were presented on a modified Bassin Anticipation Timer with presentation rate controlled by a programmed timer. The criterion velocities were 134.11, 268.22 and 402.33, cm/sec with variable velocities ranging 44.7 cm/sec above and below the criterion in 8.94 cm/sec increments. The method of constant stimuli was used with 198 trial pairs presented (constant 7 second stimulus presentation interval). The results indicated that the discrimination of horizontal linear velocity follows a prothetic continuum. That is, the just noticeable difference increased in proportion to the increase in the criterion velocity. In addition, the subjects' orientation to the stimulus and the viewing distance (length of runway) seemed to play little or no role in the discrimination process. |
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| Keywords: | visual discrimination velocity JND Weber constant prothetic difference threshold |
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