are feature detectors innate
(1971) â¢ Discriminability was measured by an increase in sucking rate toa second speech sound after habituation to the first sound. â¢ Recovery from habituation was greater when the two stimuli were from different adult phonemiccategories than when they were from the same category. Eimas et al.1971) reported that infants, like adults, demonstrate categorical ppp p perception for speech sounds. To explain this they proposed that infants are equipped with innate, speech-specific, phoneticfeature detectors tuned to the range of phonetic contrasts used in the worldâs languages.