As noted above, one can only expect retrieval practice to out- perform restudying items when retrieval practice is successful. If performance during retrieval practice is not very high, then the greater exposure from the restudy condition will overwhelm the retrieval practice benefit (Karpicke & Bauernschmidt, 2011; Karpicke & Smith, 2012). The purpose of Experiment 4 was to examine overt and covert retrieval under conditions designed to increase levels of initial retrieval success. During retrieval prac- tice, we provided more powerful cues to boost performance. This allowed us to compare retrieval practice to restudying and also to see if overt and covert retrieval practice would still produce equivalent benefits with higher levels of retrieval success. An additional feature was to include no response during covert re- trieval. In the first three experiments covert retrieval still involved some type of response (typing in the number of items in Experi- ment 1, typing an “X” in Experiments 2 and 3). In Experiment 4 we removed all forms of overt responding from the covert condi- tion. Finally, overt and covert responding were contrasted in between subjects comparisons rather than the within-subject com- parisons of the previous experiments.