The effect of word frequency and parafoveal preview on saccade length during the reading of Chinese

There are currently 2 theoretical accounts of how readers of Chinese select their saccade targets: (a) by moving their eyes to specific saccade targets (i.e., the default-targeting hypothesis) and (b) by adjusting their saccade lengths to accommodate lexical processing (i.e., the dynamic-adjustment hypothesis). In this article, we first report the results of an eye-movement experiment using a gaze-contingent boundary paradigm. This experiment demonstrates that both target-word frequency and its preview validity modulate the lengths of the saccades entering and exiting the target words, with longer saccades to/from high-frequency words when their preview was available. We then report the results of 2 simulations using computational models that instantiate the core theoretical assumptions of the default-targeting and dynamic-adjustment hypotheses. Comparisons of these simulations indicate that the dynamic-adjustment hypothesis provides a better quantitative account of the data from our experiment using fewer free parameters. We conclude by discussing evidence for dynamic saccade adjustment during the reading of alphabetic languages, and why such a heuristic may be necessary to fully explain eye-movement control during the reading of both alphabetic and nonalphabetic language