Much of the published research in infant speech perception has emphasi
zed how well infants have done with a number of speech contrasts, and
have noted similarities in pattern of discrimination of adults and inf
ants. Often it has been suggested that infants begin life with the abi
lity to perceive any speech contrast, and that the process of acquirin
g a language involves inhibition of the ability to perceive contrasts
not present in the target language. Indeed some studies have shown inf
ants able to discriminate contrasts on which adults fail if the contra
sts are not drawn from the native language of the adults. Other studie
s, however, have suggested that infants may not always be so perceptua
lly capable. The present work focusses on the stop-glide contrast. The
results are inconsistent with the prevalent view and with previously
reported studies on the perception of the stop-glide contrast by infan
ts. The results indicate that in a vigilance paradigm adapted for both
infant and adult testing, infants perform poorly on the contrasts whe
n compared with adults. Furthermore the pattern of relative perception
observed in the adults on stimuli with long or short vowels is quite
unlike that of the infants. It is concluded that much work remains in
order to evaluate the relative performance of infants and adults in sp
eech perception, since it appears that changes in experimental paradig
m or particular stimulus parameters may affect outcomes in fundamental
ways.