Noticing the hole (NTH) occurs when speakers want to say something, but realise they do not know the right word(s). Such awareness of lacking knowledge supposedly facilitates the acquisition of the unknown word(s) from later input (Swain, 1993). We tested this claim by experimentally inducing NTH in a second language (L2) for some participants (experimental), but not others (control). Then, in a price comparison game, all participants were exposed to spoken L2 input containing the to-be-learned words. They were unaware of taking part in an L2 study. Post-tests showed that participants who had noticed holes in their vocabulary had indeed learned more words compared to participants who had not. This held both for the experimental group as well as those participants in the control group who later reported to have noticed holes. Thus, when we become aware of vocabulary holes, the first step to improve our vocabulary is already taken.