Productive knowledge of derivational rules in poor readers.

The present report with two complementary experiments examined the productive knowledge of derivational morphology in 75 grade 4, 5, and 6 "poor" readers further divided into those performing better, or worse, inboth reading and spelling ((R + S +) or R - S -)), or better in the one or the other (mixed) subgroups. Experiment 1 required individual subjects to vocalize rapidly the derived forms of words when primed with 40 target base words in four derivational conditions or levels embedded in sentence frames shown on the computer screen. Experiment 2 required the reverse process of vocalizing the base forms of words when primed with 40, complex derived forms in the same four morphology conditions embedded in sentence frames shown on the computer screen. Results of the analysis of the reaction times show a developmental trend and that the subgroups of poor readers used different mechanisms in producing derived or base forms of words according to the complexity of the orthographic and/or phonological changes needed in the derivational process. The important role of morphemic structure and origin of words in instruction is emphasized.