THE INFLUENCE OF BORDERS ON INCREMENT THRESHOLDS.
PSYCHOPHYSICS LAB UNIV OF WASHINGTON SEATTLE
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Previous investigators have reported that increment thresholds are elevated in the regions of abrupt spatial changes of adapting field intensity, known as borders or edges. Such effects have often been attributed to lateral physiological interactions, particularly lateral inhibition, within the visual system. An attempt was made to determine empirically the actual cause or causes of the elevated thresholds on the high intensity side of a border. These elevated thresholds are tentatively attributed to the combined influence of two factors involuntary eye movements, which produce frequent changes of retinal illuminance near the border and transient elevations in the increment threshold which occur near the times of large, rapid changes in retinal illuminance. It is concluded that short-term lateral interactions have little if any influence on increment thresholds on the high intensity side of a border. The possibility remains, however, that such increment thresholds may be influenced by lateral interactions whose effects take an extended period of time to develop. Author
- Anatomy and Physiology