Acoustically, /w, j, r, l/ are more like vowels than other consonants. However, as with other consonants, their chief perceptual cues are formant-frequency transitions, and their articulatory specification omits some parameters, allowing coarticulation of gestures from neighboring phones. If perception reflects the “incomplete” articulatory specification, semivowels and laterals should be perceived similarly to other consonants; for stop consonants, but not vowels, perception is categorical and identifications are more accurate on the right ear than the left. On purely psychoacoustic considerations, /w, j, r, l/ with their vocalic mode of production and slower transitions, than other consonants should produce intermediate results in these experimental situations. Three experiments were performed with /w, j, r, l/. The first showed that the amount of categorical perception is similar to that in the place dimension of voiced stops; the second showed that the right-ear advantage is also similar to that for voiced stops, and a third showed that this advantage is not enhanced if transitions are of a speed more appropriate to stops. These results suggest a single mode for the perception of consonant transition information, possibly related to coarticulation. [Research begun at Haskins Laboratories.]