Young children can reason about direct and indirect visual information, but fully mapping this understanding to linguisticforms encoding the two knowledge sources appears to come later in development. In English, perception verbs with smallclause complements (I saw something happen) report direct perception of an event, while perception verbs with sententialcomplements (I saw that something happened) can report inferences about an event. In two experiments, we explore when4-9-year-old English-speaking children have linked the conceptual distinction between direct perception and inferenceto different complements expressing this distinction. We find that unlike older children or adults, 4-6-year-olds do notrecognize that see with a sentential complement can report visually-based inference, even when syntactic and contextualcues make inference interpretations highly salient. Until around age seven, children are still learning the syntax andsemantics of perception verbs like see and how distinct syntactic forms encode different kinds of perceptual experience.

Block-building is an early-developing spatial skill in which multiple spatial actions unfold over time. The processes underlying block-building have eluded our understanding, but existing data show that children’s and adults’ construction paths are highly systematic and selective. In this paper, we investigate whether manipulating the stability of block models to be built affects the character of construction paths. We asked participants to build models with either strong or weak support. We measured the step-by-step actions taken and used eye-tracking to assess differences between adults and children in how they collect and use visual information while building. We find that children and adults are highly selective in their construction paths, but models with weak support are more difficult to build, reflected in the specifics of their paths and the eye movements made during building. These results suggest that the stability of a structure drives information-gathering and building strategies in block construction.

Motion quality can differentiate experts from novices in fields like surgery (Ershad et al., 2018). We extend approaches used by researchers in that field to examine the relationship between motion and skill in a children’s block-building task. We ask whether the relationship between these two variables is detected equally well by humans and machines—in this case, motion sensors embedded in the blocks. We investigate whether adults’ judgments about motion quality and children’s overall building skill reflect children’s actual construction ability, and whether data from embedded motion sensors predict children’s skill as well as adult judgments do. We find that human raters outperform the motion sensor data. Our findings raise questions about how people form such intuitive judgments of expertise, and how automated judgments of skill can be enhanced to more accurately predict expertise in block building and other similar cognitive tasks.