INFLUENCE OF RATIO ON SOUND LOCALIZATION 
cided break in it, we do not know ; but we think it safe to assume 
that the straight line curve up to 90° is the normal type of 
curve for this kind of localization, and when there are breaks 
that something is wrong, for instance a cold may cause such an 
effect. Figure 27 shows four curves from the same observer; (1) 
and (2) are with the closed binaurals, (3) and (4) with the 
open binaurals. Number (2) shows a decided break. 
Our curves generally reach 90° when the relative intensity at 
the ears is 25 to 1. The slope and breaks of the curves for the 
“open” binaurals are about the same as for the “closed” 
binaurals. Our results so far show that the law 0=k log(I R /I L ) 
holds until we get to 80° to 90° and that(I R /I L )is about 25 when 
the angle is 90°. 
Physical Laboratory, 
The State University of Iowa. 
