This study contributes to the research on learner autonomy by examining the relationship between Little's (1991) notions of "independent action" and "decision-making", input, and L2 production in computer-assisted language learning (CALL). Operationalizing "independent action" and "decision-making" with Dam's (1995) definition that focuses on "choice", the present study examines whether, while learners are engaged in a CALL task, their choices--termed "autonomous moves"--within a 3D environment and the subsequent input they receive predict the linguistic complexity and accuracy of their production in synchronous computer mediated communication (SCMC). A total of 58 third-year university-level learners of Spanish participated in two murder-mystery tasks coupling a 3D segment--containing embedded user-tracking features--with an SCMC segment. Four regression analyses examined the potential impact of learners' choices within the 3D environment and the input resulting from those decisions on their production. The results suggest that learners' linguistic complexity and accuracy while completing CALL-based tasks is influenced by both their autonomous moves and the linguistic characteristics of the input they receive (as a result of their autonomous moves). (Contains 3 figures, 7 tables, and 2 notes.)