| Three experiments investigated the effects of noise masking and memory load on on-line syntactic processing. The studies used self-paced listening with end-of-sentence plausibility judgments. Sentences differed in syntactic complexity. In the first study, 120 undergraduate students were tested on one-proposition simple cleft-subject and complex cleft-object sentences under noise conditions that were varied between no noise, -3 dB S:N, and -4.5 dB S:N. In the second study, 135 undergraduate students were tested on two-proposition simple object-subject and complex subject-object sentences under noise conditions that were varied between no noise, -3 dB S:N, and -4.5 dB S:N. In both experiments, noise affected word recognition, as measured by repetition, in both sentence types equally, and word recognition errors did not contribute to the results. There were effects of noise and of syntactic complexity in self-paced listening times and in plausibility judgments. In the self-paced listening data, listening times increased at the embedded verb of object-relativized sentences, reflecting the increase in load at that point. There were no interactions of noise and complexity in the self-paced listening times. Syntactic complexity effects, or interactions between noise and complexity, were found in the end-of-sentence plausibility judgments. In the third experiment, 36 undergraduate students were tested under concurrent load conditions that were varied between no load, a 3 digit load, and a 5 digit load. There were effects of load and of syntactic complexity in digit recall, plausibility judgments and in self-paced listening times. In the self-paced listening data, listening times increased at the embedded verb of object-relativized sentences, reflecting the increase in load at that point. As opposed to results of the noise masking experiments, there were no interactions of load and complexity in any performances. Taken together, results suggest that on-line construction of syntactic structure is not affected by either a concurrent memory load or concurrent noise. Results also indicate that the processes involved in performing operations on the meaning of sentences, such as evaluating their truth value, are affected by concurrent noise. |
