For learning morphological rules, production tasks are no better than comprehension

This paper weaves together two strands of previous research: one which identifies that adults struggle to learn morphological rules, and another which indicates that language learning can be facilitated by language production. Here, we ask: can a production task help adults learn morphological rules? In two artificial language learning experiments, we taught participants a language that indicated thematic role with both a fixed word order (a word-level rule, which should be easier for adults to learn) and case marking (a morphological rule, which should be harder for adults to learn). We manipulated whether participants practised this artificial language using a comprehension task or a production task, and then asked whether participants who did the production task were more likely to learn the case marking rule. We also assessed how aware participants were of the morphological pattern that results from the case marking, even if they did not associate certain markers with certain thematic roles per se. Experiment 1 tested L1 English participants, and Experiment 2 tested L1 German participants: populations that differ in their prior experience of case. In both experiments, we found that participants across the board failed to learn the case marking rule, even though the majority did detect the morphological pattern that was the consequence of case marking. We conclude that the production task we used in this study did not suffice to help adults learn a less accessible morphological rule.