Saccadic targeting in the Landolt-C task: implications for Chinese reading

Participants in an eye-movement experiment performed a modified version of the Landolt-C paradigm (Williams & Pollatsek, 2007) to determine if there are preferred viewing locations when they searched for target squares embedded in linear arrays of spatially contiguous clusters of squares (i.e., sequences of one to four squares having missing segments of variable size and orientation). The results of this experiment indicate that, although the peaks of the single- and first-of-multiple-fixation landing-site distributions were respectively located near the centers and beginnings of the clusters, thereby replicating previous patterns that have been interpreted as evidence for the default saccadic-targeting hypothesis, the same dissociation was evident on nonclusters (i.e., arbitrarily defined regions of analysis). Furthermore, properties of the clusters (e.g., character number and gap size) influenced fixation durations and forward saccade length, suggesting that ongoing stimulus processing affects decisions about when and where (i.e., how far) to move the eyes. Finally, results of simulations using simple oculomotor-based, default-targeting, and dynamic-adjustment models indicated that the latter performed better than the other two, suggesting that the dynamic-adjustment strategy likely reflects the basic perceptual and motor constraints shared by a variety of visual tasks, rather than being specific to Chinese reading. The theoretical implications of these results for existing and future accounts of eye-movement control are discussed.