Linking cognitive control to language comprehension: proportion congruency effects in syntactic ambiguity resolution

Two experiments investigated the effect of sustained cognitive control engagement on syntactic ambiguity resolution. Participants heard (Experiment 1) or read (Experiment 2) garden path sentences like "Put the kiwi on the rectangle on the circle", in which "on the rectangle" could temporarily reflect either a destination of "Put" or modifier of "kiwi", and they viewed visual arrays with a kiwi on a rectangle and an empty rectangle and circle. Cognitive control was manipulated experimentally by interleaving sentence trials among either mostly incongruent or mostly congruent Stroop trials. Across both experiments, garden path mouse cursor movements to incorrect destinations were reduced when sentence trials were interleaved among mostly incongruent Stroop trials, and in Experiment 2, garden path reading time effects were also reduced in this condition. These results suggest that a high proportion of incongruent trials supports the sustained engagement of cognitive control and causally improves sentence comprehension across (i.e. spoken and written) modalities.