No Correlation between Rod-and-Frame and Visual Normalization Scores

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It has been suggested that the Rod-and-frame Test is correlated with personality measures and cognitive-perceptual measures like the embedded figures test (4). The present study inquired whether scores on the rod-and-frame are correlated with scores on a measure of visual normalization (1 ). It was posited that differences in responses on the rod-and-frame might depend on the amount of visual normalization occurring during judgment of vertical on the test. Some normalization effect has been shown to occur within a short period of time, 1.5' after as little as 45 sec. inspection (1). Ss making their own rod adjustments may take as long as 45 sec. to reach a satisfactory adjustment. This period would be sufficient for the development of some visual normalization. Ss who tended to show a large visual normalization effect might be expected to show an unusually large score. when scores are calculated with reference to direction of tilt (2). In the absence of visual normalization, S's rod-and-frame judgment depends on some compromise between the frame effect and his ordinary perception of visual vertical as determined by the pull of gravity and other factors. Visual normalization alrers the judgment of visual vertical and thus changes the perceptual data which enter into the compromise. Let us assume that visual normalization is most influenced by the direction of tilt of the largest object in the field, in this case the frame. Now consider S observing a tilted rod in a left-tilted frame. The frame effect pulls S's adjustment of the rod to the left of vertical. Visual normalization simultaneously alters subjective vertical leftward. Thus, both the frame effect and the normalization effect are pulling subjective visual vertical in the direction of frame tilt. and Swill choose as vertical a more left-tilted rod than he would choose in the absence of any normalization effect. Individual differences in visual normalization might thus contribute to individual differences in rod-and-frame scores, with a positive correlation berween rod-and-frame scores and visual normalization scores. The present study tested 37 male Ss. ranging in age from 18 to 30 yr., on the rod-andframe test, using a procedure which has been described elsewhere (3). Normalization was measured with the rod-and-frame, the frame portion covered with a cylinder of white paper. S scanned a line tilted 10 from vertical for 5 min., then adjusted lines to apparent vertical 4 times. The lines' starting positions were 10 off vertical, alternating right and left starting positions. The pretest control readings from the rod-and-frame measure were also used as control read~ngs here. The measures were not significantly correlated (p = 0.05, df = 36, p > .05). The suggested influence of visual normalization on rod-and-frame scores was not supported. REFERENCES