Mechanisms for the Perception of Concurrent Vowels (original) (raw)

Previous research has shown that the perceptual segregation of concurrent vowels is improved when there is a difference in fundamental frequency (F0) between them. Two theories, termed F0-guided segregation and glottal pulse asynchrony (GPA), have been advanced to explain this "∆F0 effect". A previous study found no consistent effect of GPA. However it is argued that this may have been because the auditory system uses both strategies, in which case a common F0 may cause the two vowels to be heard as one regardless of GPA. To overcome this potentially confounding influence, vowels with irregularly timed glottal pulses (and thus no well defined F0) were used to investigate the role of GPA. The results show that GPA still has no significant effect on recognition rates. Remarkably however, these irregularly excited vowels gave recognition rates that were equal to or significantly greater than their periodic counterparts, suggesting that F0-guided segregation is not required to explain the ∆F0 effect.