Where do "constraints" come from? A comparison between inferences in biology and in word learning

In this paper, as a commentary on the papers in this special issue, the nat ure of constraints is discussed in terms of the comparison between inferenc es in biology and in word learning. Young children's inferences in biology could be constrained by three sources of information: factual knowledge, ex pectations based on a theory, and ontological knowledge. For example, young children's inference about the length of noses could be constrained by the facts the children know about the animals, the similarity between the anim als and humans, and the ontological distinction between living things and n onliving things. In the same way, young children might figure out word mean ings by linguistic and pragmatic knowledge, expectations of word meanings ( e.g., the whole-object assumption), and ontological knowledge. Interactions among these sources of knowledge are documented by the papers in this spec ial issue and related studies. It is argued that learning biases such as th e whole-object assumption could not be induced only by linguistic and pragm atic cues in a social context, but should be regarded as a product of the i nteraction between a social context and children's theories.