The keyword mnemonic and retrieval practice are two cognitive techniques that have each been identified to enhance foreign language vocabulary learning. However, little is known about the use of these techniques in combination. Previous demonstrations of retrieval-practice effects in foreign language vocabulary learning have tended to use several rounds of retrieval practice. In contrast, we focused on a situation in which retrieval practice was limited to twice per item. For this situation, it is unclear whether retrieval practice will be effective relative to restudying. We advance the view that the keyword mnemonic catalyzes the effectiveness of retrieval practice in this learning context. Experiment 1 (48-h delay) partially supported this view, such that there was no testing effect with retrieval practice alone, but the keyword-retrieval combination did not promote better retention than keyword alone. Experiments 2 and 3 (1-week delay) supported the catalytic view by showing that the keyword-retrieval combination was better than keyword alone, but in the absence of keyword encoding there was no retrieval practice effect (replicating Experiment 1). However, with four rounds of retrieval practice, a marginally significant testing effect emerged (Experiment 3). Moreover, the routes through which participants reached each answer were identified by asking retrieval-route questions in Experiments 2 and 3. Keyword-mediated retrieval, which was observed sometimes even in no-keyword instructed conditions, was shown to be more effective than unmediated retrieval. Our findings suggest that incorporating effective encoding techniques prior to retrieval practice could augment the effectiveness of retrieval practice, at least for vocabulary learning.
Keywords: Foreign language vocabulary learning; Retrieval practice; Testing effect; The keyword mnemonic.