DEATON, J. A., & GERNSBACHER, M. A. (in press). Causal conjunctions and implicit causality cue mapping in sentence comprehension. Journal of Memory and Language.
Five experiments investigated whether readers use the causal conjunction because as a cue to map two clauses onto the same mental representation. In Experiments 1 and 2, two-clause sentences that described moderately causally related events were read more rapidly when the two clauses were conjoined by because (Susan called the doctor for help because the baby cried in his playpen) than when they were conjoined by and (Susan called the doctor for help and the baby cried in his playpen) or then (Susan called the doctor for help then the baby cried in his playpen). When the two clauses were conjoined by because, the second clauses were also recalled more frequently in a prompted recall test. Experiments 3 and 4 demonstrated that the facilitative effect of because depends on the clauses' causal relatedness: Unrelated clauses were read least rapidly and recalled least frequently, regardless of their conjunctions. But as the clauses' causal relatedness increased, the second clauses of sentences conjoined by because were read more rapidly and recalled more frequently. Experiment 5 demonstrated that the facilitative effect of because versus other conjunctions was not due to the fact that the clauses in our experimental sentences were presented in an order more conducive for the conjunction because. We conclude that causal conjunctions and causal relations are cues for structure building: Moderate to high causal relatedness yoked with the conjunction because encourages readers to map the two clauses onto the same mental structure.