Perceptual restoration of filtered vowels with added noise

Perceptual restoration is a well-known phenomenon for speech segments in context, but less is known about the effect for stimuli that occur without a linguistic context. The current study investigated restoration in the perception of isolated vowels. Vowels excised from natural speech were lowpass filtered (1000 Hz), which removed the high F2 characteristic of front vowels. This resulted in high rates of front to back vowel confusions; however, these errors were reduced when highpass filtered noise was added to the lowpass filtered vowels. Although the reduction in errors was accompanied by an increase in back to front vowel errors, addition of noise led to improved performance overall. These results suggest that listeners "restored" the high F2 of front vowels in the noise condition, despite an absence of linguistic context to influence restoration, and that addition of noise led to more effective utilization of cues below 1000 Hz.