The effect of equal versus expanding spacing practice on the deliberate learning of L2 collocations

Research comparing equal and expanding spacing schedules in relation to L2 single words is limited. Moreover, none of the existing studies has examined the learning of formulaic language. The current study aims to address this gap by investigating the impact of equal and expanding intervals on the long-term retention of L2 collocations in deliberate learning contexts. Eighty-three university learners of English l (L1 Arabic) participated in the study. They were divided into three groups: equal spacing (7-7-7) condition, expanding spacing (1-5-15) condition, and a control condition (no exposure). The experimental groups completed four treatment sessions in which they were asked to deliberately learn 23 collocations. To assess collocation knowledge before and after the treatment, all groups took form recall and form recognition tests. Results show that both spacing conditions led to significantly higher gains than the control group in both tests. The difference between the two experimental groups was not significant for the recall measure but it was significant for the recognition measure (higher gains under 'equal spacing'). Moreover, estimated language proficiency modulated the difference between the control and expanding conditions, with a sharper difference as proficiency increased. Important implications for language teaching and classroom instruction based on these findings are discussed.