"Three adult male subjects viewed two vertical black test rods . . … The lower rod was moved either in the frontal or in the median plane and was judged in reference to the upper rod. Five widths of test rods were used . . … The differences between any two mean thresholds in either the real depth situation or the vernier were not significant at the five percent level . . … It is concluded that changing the angular widths of the test objects within the limits of the present experiment does not significantly affect either vernier or the real depth thresholds." (PsycINFO Database Record (c) 2006 APA, all rights reserved)