This study was designed to investigate the influence of the presence and orientation of figures proximal to an acuity measurement line. Each of 16 Ss served under four conditions: acuity line alone, acuity line with proximal figures parallel with it, acuity line with 45° proximal figures, and acuity line with 90° proximal figures. All proximal figures tested resulted in decreased efficiency of acuity processes. Orientation of the proximal figure was an important factor with greater influence for 45° and 90° than for the parallel line situation. These results support the Fry-Bartley principle that contour processes interfere with each other and indicate that the influence is directional in character.
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