A report of an experiment to measure the effects of both overt and covert responses to educational stimuli with KCR (knowledge of correct results) feedback provided. In most studies of feedback, KCR (or KR) is given as a consequence of an overt response: Stimulus-Response-Feedback. In the case of a covert response, the student constructs his answer but does not react "overtly" to the presentation of a stimulus item. Forty Ss were randomly assigned to 1 of 4 groups further divided into 1 control group receiving no feedback and 3 groups receiving information (KCR) according to either overt or covert response patterns. A 25-item multiple-choice test was administered 5 times by means of a terminal consisting of a screen and a teletype. Results showed that the covert paradigm was the most effective. The experiment did not demonstrate that the covert process leads to better performance on a test administered later to measure retention. A tentative explanation for this negative result was that the time interval between the provision of feedback and presentation of the next item was of some relevance. A multiple comparison test revealed that the 3 treatment groups performed better than the control group.