Metacognitive activities were studied through the verbalizations of students during a learning process, to study the differences in the performance of good and poor students. The moment of verbalization, either at prompting marks or without prompts, and the instruction in verbalization, either directed or non-directed, were variables. Thirty-two girls and 32 boys in the first year of Dutch comprehensive school, half good performers and half poor performers according to school records, participated. Half were instructed to verbalize only at marks occurring during the learning of lists of English vocabulary words and Dutch translations; half were to verbalize throughout the learning process. Half received directed instruction and half did not. Thinking-aloud protocols were tape-recorded and analyzed. Analyses of variance indicated that the two variables "moment of verbalization" and "instruction" did not have any effect on performance. Both variables also had no effect on the total quantity of verbalization. Most students, however, could not restrict themselves to verbalizing only at the marking points, and most verbalized between marks as well. To keep verbalizations focused on the task, instruction was helpful. Good students apparently interrupted their recalling action during learning by checking and noting their own accuracy more often than did poor students. Six tables present study data. (SLD)