SUMMARY
Both cognition and affect have been proven to have a significant role in instructed second language acquisition. Unlike cognitive processes, the affective processes in language learning have not received due attention in the research on task-based language teaching. The effect of task-related emotional state on learning achievements resulting from task engagement is an almost unexplored area. The study reported here investigated the effect of emotional involvement as compared to cognitive involvement both applied to the pre-task phase of a reading-while-listening focused task on lexical acquisition as a result of engagement with the task. Emotional involvement was operationalized as a video clip shown before the main task which elicited positive affect. MANCOVA statistics indicated that both emotional and cognitive involvements had an enhancing effect on short-term retention and ease of activation of vocabulary. However, the enhancing effect was not observed for long-term acquisition. The findings imply pedagogical suggestions for task-based vocabulary teaching.