Eye movements and morphological segmentation of compound words: There is a mouse in mousetrap

In two experiments, readers' eye movements were monitored as they read sentences containing compound words. In Experiment 1, the frequency of the first and second morpheme was manipulated in compound words of low whole word frequency. Experiment 2 compared pairs of low frequency compounds with high and low frequency first morphemes but identical second morphemes that were embedded in the same sentence frames. The results showed significant effects of the frequency of both morphemes on gaze duration and total fixation time on the compound words. Regression analyses revealed an influence of whole word frequency on the same measures. The results suggest that morphemic constituents of compound words are activated in the course of retrieving the representation of the whole compound word. The fact that the frequency effects were not confined to fixations on the morphemic constituents themselves implies that saccadic eye movements are implemented before morphemic retrieval has been completed. The results highlight the importance of developing more precise models of the perceptual processes underlying reading and how they interact with the processes involved in lexical retrieval and comprehension.