Abstract

This study investigates the effects of vocabulary instruction on learner’s task engagement, flow, and vocabulary learning through video viewing, as well as the role of task motivation in these outcomes. Task engagement refers to learner’s heightened attention to and involvement in a task across multiple dimensions (Philp & Duchesne, 2016). Given the individual nature of video viewing, the present study focuses on cognitive and emotional engagement. Although pre-teaching vocabulary may facilitate comprehension by reducing the burden of unknown words, such support may also alter how learners attend to and experience meaning-focused viewing. Approximately 280 Japanese university students participated in a four-week classroom study and were assigned to pre-teaching, post-teaching, or test-only control conditions. Participants in the two experimental conditions viewed an approximately 11-minute episode of Our Planet 2 with vocabulary instruction administered either before or after viewing. Vocabulary learning was assessed through form recognition, meaning recall, and meaning recognition tests administered two weeks before the treatment and one week afterward. Cognitive and emotional engagement and flow were measured using post-viewing questionnaires. Task motivation was conceptualized through situated expectancy-value theory (SEVT; Eccles & Wigfield, 2020), encompassing expectancy for success, subjective task value, and perceived task costs, and was measured prior to the main treatment. The study examines whether instructional timing differentially affects engagement, flow, and vocabulary learning, and whether task motivation is associated with these outcomes. By examining both psychological and lexical consequences of instructional timing, this study seeks to inform vocabulary support in meaning-focused video viewing. Additionally, follow-up interviews were conducted to gain a more detailed understanding of the learner's cognitive and emotional experiences during viewing.The results will be presented and discussed at the conference.