Word-recognition behavior of 50 high school students two or more grade levels below their age mates in tests of reading comprehension was contrasted with that of 25 controls from the same schools, who were reading at grade level. The experiment included a section in which pictures (flashed, like the words, at 1/100 of a second) were to be identified, in order to explore the relationship of word-perception difficulties to broader visual-perception problems. Results indicated that adolescents with low reading-comprehension scores also had difficulty reading individual words presented at short flash durations, though they did not have difficulty recognizing pictures. Regression analyses indicated that such factors as length, frequency, concreteness, and pleasantness were good predictors of test-subjects' errors (but not of controls' errors). Such factors as word stress pattern, grammatical category, and morphological and derivational complexity also affected the recognition success of test subjects but not of controls. There were qualitative, as well as quantitative, differences between the errors made by test subjects and by controls. (Author/AA)