Investigating optimal spacing schedules for incidental acquisition of L2 collocations

Abstract Research investigating lag effects in second language (L2) collocation learning is very limited. To date, no intervention study has examined the relationship between intersession intervals (ISIs) and retention intervals (RIs) in relation to incidental acquisition of collocations. To fill this gap, the current study collected data from two groups of students in Saudi Arabia (Experiment 1, n = 73; Experiment 2, n = 69), using a pretest-treatment-delayed posttest design. The participants learned 25 incongruent adjective-noun collocations incidentally during five reading sessions at either a 3.5-day ISI (Experiment 1) or a 7-day ISI (Experiment 2). Two control groups received no treatment. Learning rates were assessed at the form recall and meaning recall levels of sensitivity following an RI of 14 days in Experiment 1 and an RI of 28 days in Experiment 2. Results show that both spacing schedules were equally effective for the incidental acquisition of collocations.