Cognitive fatigue induced by spaced and massed practice: effects on idiom accuracy across L2 proficiency levels

Abstract This study investigated the effects of spaced and massed practice on cognitive fatigue across L2 proficiency levels. 92 L2 learners completed idiom comprehension tasks under spaced and massed practice conditions and then the five dimensions of their cognitive fatigue (cognitive, emotional, physical, behavioral, and motivational) were measured in two ways: perceived cognitive fatigue through a self-report scale and performance-based cognitive fatigue via a free recall idiom accuracy test. Results revealed that spaced practice significantly reduced overall cognitive fatigue, with the effect being most pronounced among low-proficiency learners. Results also indicated significant interactions between practice type and proficiency level across all fatigue dimensions. Multiple regression further demonstrated that while cognitive engagement positively predicted idiom comprehension accuracy, physical fatigue emerged as the strongest negative predictor. These results have important implications for L2 pedagogy, highlighting the need for differentiated instruction that considers practice distribution and learners’ susceptibility to various dimensions of cognitive fatigue.