Identification de voyelles simultanées harmoniques et inharmoniques

It is known that the auditory system uses harmonicity cues to separate concurrent voiced sounds that differ in fundamental frequency (FO). What is less clear is whether the harmonicity of the target sound is used to enhance it within the mixture, or whether that of the background is used to cancel it and thus allow the target to emerge. An experiment was designed to answer this question. Subjects were presented with pairs of concurrent synthetic vowels, each of which was either harmonic or inharmonic. Results were scored according to the harmonicity of the vowel identified (the target), and that of the second vowel (the ground). For a given target, identification was best for harmonic grounds, except when target and ground were both harmonic and had the same FO. This is compatible with the cancellation hypothesis. On the other hand, identification for a given ground was worse when the target was harmonic. This is the opposite of the effect predicted by the enhancement hypothesis