The present paper provides evidence that suggests that speakers determinewhich constructions can be combined, at least in part, on the basis of thecompatibility of the information structure properties of the constructions in-volved. The relative ‘‘island’’ status of the following sentence complementconstructions are investigated: ‘‘bridge’’ verb complements, manner-of-speaking verb complements and factive verb complements. Questionnairedata is reported that demonstrates a strong correlation between acceptabil-ity judgments and a negation test used to operationalize the notion of‘‘backgroundedness’’. Semantic similarity of the main verbs involved tothinkorsay(the two verbs that are found most frequently in long-distanceextraction from complement clauses) did not account for any variance; thisfinding undermines an account which might predict acceptability by analogyto a fixed formula involvingthinkorsay. While the standard subjacencyaccount also does not predict the results, the findings strongly support theidea that constructions act as islands to wh-extraction to the degree thatthey are backgrounded in discourse.