Recent studies, together with others dating back as far as 1851, leave little doubt that the cavities and convolutions of the pinnae play an important role in the localization of signals that originate in the median plane. Less clearly understood, however, is the nature of the clues that are utilized in arriving at a localization decision. Results of the present study indicate that, insofar as localization in the anterior sector of the median plane is concerned, clues associated with the cavities of the pinna have an important monaural component. Binaural reception also plays a significant role including confining the apparent location of the resultant image within, or near, the median plane. Such a centralizing influence is an essential requirement for optimizing this type of localization. Clues of a secondary nature were found to be associated with the range of frequencies between about 0.7 and 3.5 kHz.