This chapter focuses on the possible functional differences between modal and amodal completion in relation to visual attention. A review of visual-search experiments suggests that both modal and amodal completion may arise preattentively, that is, at parallel stages of vision, and even when counter to the observer's intentions. However, the two forms of completion may then differ in their effect upon attention, with attention tending to spread between inducing fragments and completed regions only for the case of modal completion, for which filling-in arises in the completed region.

This chapter focuses on the possible functional differences between modal and amodal completion in relation to visual attention. A review of visual-search experiments suggests that both modal and amodal completion may arise preattentively, that is, at parallel stages of vision, and even when counter to the observer's intentions. However, the two forms of completion may then differ in their effect upon attention, with attention tending to spread between inducing fragments and completed regions only for the case of modal completion, for which filling-in arises in the completed region.