[Categorical factors in the oblique effect under successive and absolute judgments of inclination]

Effects of inclined frame of reference upon inclination of the target line have been studied under successive and absolute judgments. Using nine undergraduate students as subjects, a marked oblique effect on the distribution of judgment errors was found under the condition with the horizontal frame of reference. In contrast, the peak of errors shifted in proportion to the inclination of the frame of reference and the relative dominance disappeared on physically horizontal and vertical axes. Some familiarized response categories such as 0 degrees, 30 degrees, 45 degrees, 90 degrees and -30 degrees were utilized more frequently than the others, and this tendency was found to be similar in every subjects and conditions. These consequences couldn't be attributed to the anisotropy of orientation analyzers, therefore, the obtained results have been explained in terms of the anchoring effect during categorization processes.