“…This question has been answered in three competing ways. First, listeners have learned that the acoustic properties covary reliably (Nearey, 1990(Nearey, , 1997Kluender, 1994;Holt, Lotto, & Kluender, 2001); second, the acoustic properties result from a single gesture (motor theory : Liberman, Cooper, Shankweiler, & Studdert-Kennedy, 1967;Liberman & Mattingly, 1985;direct realism: Fowler, 1986direct realism: Fowler, , 1990direct realism: Fowler, , 1991direct realism: Fowler, , 1992direct realism: Fowler, , 1996; or third, the acoustic properties produce similar auditory effects (Parker, Diehl, & Kluender, 1986;Kingston, Diehl, Kluender, & Parker, 1990;Diehl & Kingston, 1991;Kingston & Diehl, 1994. We will call these alternatives the "associative," "gestural," and "auditory" explanations, respectively.…”