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Developmental Change in Readers' Responses to Unknown Words

Two experiments examined factors affecting the likelihood that readers will recognize failures of word comprehension and the basis by which they judge the disruptiveness of an unknown word to sentence comprehension. In Experiment 1, third- and fifth-grade skilled and less skilled readers read and evaluated the comprehensibility of short paragraphs containing nonwords varying in number of syllables (1 vs. 3) and syntactic form class (noun vs. adjective). Third graders were more likely to identify the longer nonwords as problematic than the shorter non-words, but the fifth graders were not influenced by word length. Fifth graders were somewhat more sensitive to the greater disruption in comprehensibility caused by unknown nouns relative to unknown adjectives. In a second task in Experiment 1, and in Experiment 2 (which included adults as well as third- and fifth-grade average readers), subjects evaluated the relative comprehensibility of pairs of sentences in which the nonwords contrasted in number of syllables, syntactic class or both. Whereas the younger readers were more likely to focus on word length in their judgments of comprehensibility, the older readers were more likely to focus on meaning. The results have implications for research and instruction in comprehension monitoring and vocabulary acquisition.