مشخصات پژوهش

Vocabulary acquisition remains a persistent challenge in Second Language Acquisition (SLA), particularly for adolescent learners whose cognitive engagement patterns differ from adults. This study investigates the impact of task-induced cognitive load on the incidental vocabulary acquisition and long-term retention of 40 Iranian EFL adolescent learners (14-year-old 8th graders). Grounded in the Involvement Load Hypothesis (ILH) and Cognitive Load Theory (CLT), the research specifically examines the "Evaluation" component to determine if qualitative increases in mental effort lead to superior learning outcomes. Using a within-group experimental design, participants will complete three reading-based tasks with systematically varied involvement loads: Task 1 (Low Load: Reading and comprehension), Task 2 (Moderate Load: Reading and sentence writing), and Task 3 (High Load: Decision-making and justification). To manage the cognitive resources of 8th-grade learners, Task 3 utilizes a "low-writing volume" approach that prioritizes semantic analysis over production anxiety. Vocabulary knowledge will be assessed through immediate and delayed post-tests measuring both receptive and productive mastery. The findings aim to verify the predictive power of the ILH in younger populations and identify the optimal cognitive load that maximizes "Germane Load" without causing cognitive overload. This research provides pedagogical implications for curriculum designers and EFL teachers seeking to optimize task design for durable vocabulary retention in the Iranian secondary education context