A specific skill necessary to expand vocabulary is that of acquiring additional meanings for words that have common, already known meanings. A study was conducted to determine if presenting subjects with the known meaning of a word before requiring them to learn a new meaning for it would result in a learning detriment. The study used homonyms whose common meanings were known and whose uncommon meanings were unknown to 40 grade 2 and 40 grade 6 children who were placed in four treatment groups, in which either (1) both the known and to-be-learned meanings of the words were presented; or (2) only the to-be-learned meaning was presented; either (3) with; or (4) without a picture illustrating the to-be-learned meaning. A posttest on the to-be-learned meanings was given to each child immediately after the reading of the text, after which three Piagetian classification tasks were administered. A follow-up test was administered to all children a week later. The results supported the view that some reading comprehension problems may stem from a reader's inability or unwillingness to discard a schema when passage context indicates that it has become inappropriate. This may be due either to the inability to use context, or to ignoring clues that should signal a shift in meaning. It appears that this aspect of acquiring meaning may be developmentally influenced, since second and sixth grade children performed differently both in reading and on the classification tasks. (FL)