ANGULAR INDUCTION IS MODULATED BY THE ORIENTATION OF THE TEST SEGMENTBUT NOT ITS LENGTH

Angular induction is the basic process by which the orientation of lin e segments can affect the perceived orientation of other segments as w ell as their alignment. In this laboratory, we have found that the eff ect on alignment follows approximately linear rules, with the inducing seg. ment having its greatest influence when its orientation is near to that of the segment being judged. Other laboratories, however, have reported peak effects when the relative angle between the two is at 4 5 degrees, and with the inducing segment being aligned with one of the cardinal axes of the observer. It has been said that the length of th e test segment being judged is a critical factor, but the first experi ment of the present study shows a similar linear decline of induction strength irrespective of test segment length. The second experiment in dicates that the orientation of the test segment relative to the obser ver modulates the induction to determine the location of peak effects. A two-factor linear model predicts the observed pattern of results.