Developmental changes in the precision of visual concept knowledge

How precise are the visual representations that underlie children’s understanding of words, and how does this precision change across development? We assessed children’s visual vocabulary knowledge in a game where children heard a word (e.g., “swordfish”) and had to choose a matching picture. Distractors were chosen to vary in their linguistic similarity to each target word in a multimodal language model. We collected data from a large sample of children (N = 3575, 3–14 year olds) and adults (N = 211 adults) and found gradual changes over developmental age ranges in participants’ ability to identify the image that a word referred to. When children made errors, younger children were more likely to choose unrelated distractors than older children; error patterns were best explained by combining linguistic and visual similarity. These results highlight that children have partial knowledge about many visual concepts and document a transition from coarse to finer-grained representations.