Even young children make multiple predictions in the complex visual world.

Children can anticipate upcoming input in sentences with semantically constraining verbs. In the visual world, the sentence context is used to anticipatorily fixate the only object matching potential sentence continuations. Adults can process even multiple visual objects in parallel when predicting language. This study examined whether young children can also maintain multiple prediction options in parallel during language processing. In addition, we aimed at replicating the finding that children's receptive vocabulary size modulates their prediction. German children (5-6 years, n = 26) and adults (19-40 years, n = 37) listened to 32 subject-verb-object sentences with semantically constraining verbs (e.g., "The father eats the waffle") while looking at visual scenes of four objects. The number of objects being consistent with the verb constraints (e.g., being edible) varied among 0, 1, 3, and 4. A linear mixed effects model on the proportion of target fixations with the effect coded factors condition (i.e., the number of consistent objects), time window, and age group revealed that upon hearing the verb, children and adults anticipatorily fixated the single visual object, or even multiple visual objects, being consistent with the verb constraints, whereas inconsistent objects were fixated less. This provides first evidence that, comparable to adults, young children maintain multiple prediction options in parallel. Moreover, children with larger receptive vocabulary sizes (Peabody Picture Vocabulary Test) anticipatorily fixated potential targets more often than those with smaller ones, showing that verbal abilities affect children's prediction in the complex visual world.