When 77 college students were asked a certain type of question after every four pages of a 48-page oceanography text that they were reading, it was found that the text information relevant to questions was learned better than text information irrelevant to questions. Furthermore, reading times and probe reaction times on a secondary task were longer when subjects were processing text segments containing information of the type addressed by questions. These results can be accounted for by a "volume of attention" theory asserting that readers selectively allocate a greater volume of attention to question-relevant information, and that a process supported by the additional attention causes more of the information to be learned. This theory was found to account for somewhat more than two-thirds of the indirect effect of questions and one-third of the direct effect of questions. (Author/RL)