It is shown in this paper that that in Kavalan and some Formosan languages, verbs in object-control complements are required to undergo causativization. We argue that the peculiar requirement may be due to a well-observed constraint, i.e., the Actor-sensitivity constraint, which in turn follows from the morphological properties of voice affixes attested in these languages. It follows that that control dependency should be thematically determined rather than grammatically determined, a conclusion against the standard structural approach.