To examine the difference in attention capacity when reading difficult or easy text, a study presented text that varied in difficulty to 22 subjects via a computer monitor. The text was presented in a self-paced manner, one word at a time. Reading times for each word were obtained by computing latencies between key presses. Whenever a flashing visual probe appeared on the screen, subjects pressed a second key. Latencies from probe onset to response were computed. Subjects read 12 passages, 6 difficult and 6 easy (rated by non-participating subjects). Passages were randomized and subjects were responsible for answering four comprehension questions following each passage. Interspersed within each passage were eight predesignated target words on which the probe was presented. Target words were matched for word frequency, length, and number of syllables across the easy and difficult passages. A second experiment used the same procedure except that the probe type varied. In half of the passages, the probe was presented visually as before, while in the other half the probe was presented auditorily (a 1000 Hz tone). Results revealed that response latencies to both auditory and visual probes were longer when the probes were presented in difficult text than when presented in easy text. The attentional capacity demands of difficult texts were shown to be greater than those of easy texts irrespective of the modality in which the probes were presented. (Two tables of data and one figure are appended.) (MM)