RECASTS AND SECOND LANGUAGE DEVELOPMENT
Recasts have figured prominently in recent SLA research, with studies documenting significant advantages for learners exposed to this type of negative feedback. Although some researchers have suggested that such findings imply a beneficial role for negative evidence (i.e., information regarding the impossibility of certain utterances in the language being learned), the source of these benefits has not been explored directly, as multiple variables are conflated in recasts. Specifically, recasts not only offer implicit negative evidence, but they also provide positive evidence. Moreover, recasts are believed to make this positive evidence especially salient. In the present study, 74 learners of L2 Spanish engaged in communicative interaction with the researcher in one of the following conditions: (a) recasts (i.e., negative evidence and enhanced salience of positive evidence), (b) negative evidence, (c) enhanced salience of positive evidence, and (d) unenhanced positive evidence (control). Only the recast and enhanced-salience groups performed significantly better than the control group on posttreatment measures, which suggests that the utility of recasts is derived at least in part from enhanced salience of positive evidence and that the implicit negative evidence they seem to provide may not be a crucial factor.