“…One reason why Gibson's (1979) general theory of perception has seemed unlikely to serve as a useful basis on which to develop a theory of speech perception (see Fowler, 1986 and the following commentary) is that the phonological or phonetic primitives that a listener is presumed to recover-phonetic features, for example-are generally not considered to cause, in an unmediated way, the structuring of the acoustic speech signal. That is, features are believed to be in the mind of the talker, and not to be transparently reflected in the vocal-tract actions that do causally structure the signal (e.g., Hammarberg, 1976;Pierrehumbert, 1990;Repp, 1981). Both in the field of linguistics, however (e.g., Browman & Goldstein, 1990), and in psychology (Fowler, Rubin, Remez, & Turvey, 1980;Saltzman & Kelso, 1987), theories are under development in which phonological primitives are presumed to be gestures of the vocal tract.…”