What does it mean that phonemes are perceived categorically? Explain how Eimas et al. (1971) demonstrate categorical perception of phonemes in infants.

What does it mean that phonemes are perceived categorically? Explain how Eimas et al. (1971) demonstrate categorical perception of phonemes in infants.

That means that when a characteristic of the speech stimulus (voice onset time) changes over a wide range, people tend to hear only two categories of sound. E.g. "da" and "ta". Therefore categorize. Peter Eimas studied the infant speech perception by using the habituation procedure to show that infants as young as one month old perform similarily to adults in categorical perception experiments. Eimas observed that an infant will suck on a nipple in order to hear a series of brief speech sounds, but as the same speech sounds are repeated, the infant's sucking eventually habituates to a low level. By presenting a new stimulus after the rate of sucking had decreased, Eimas determined whether an infant perceived the new stimulus as sounding the same or different from the old one.