Early vocabulary composition
Creators: name: Abdelrahim, Samah
Publisher: name: OSF Registries
Year: 2024
Subjects: subject: Developmental Psychology
subject: Social and Behavioral Sciences
subject: Psychology
subject: FOS: Psychology

description: Children learn word meanings quickly despite the large number of logically-possible hypotheses about the meaning of each individual word [@quine1954]. For example, upon hearing the word "spoon" in the presence of a spoon, plate, fork, food, how would they know if the word "spoon" refers to the spoon object, its color, just the oval part of the object but not the rest, or this specific spoon but not other spoon-like objects? In response to this challenge, researchers have proposed a variety of innate constraints, learned biases, and reasoning processes that could potentially help children identify word meanings. One well-studied proposal is the *shape bias*: the tendency of children to generalize by the shape of objects more than other attributes like color, texture, or size when mapping a newly learned noun to a referent [@imai_childrens_1994; @landau1988]. 
One proposal argues that children acquire the shape bias by generalizing the lexical statistics of their language. The early vocabulary of English-speaking children in the US is predominantly comprised of nouns referring to solid objects, suggesting that the shape bias may be an "over-hypothesis" that nouns tend to generalize in the same way as one another [@gershkoff2004shape; @samuelson_statistical_2002; @samuelson1999; @perry2010learn; @colunga2000learning; @yoshida2003known]. Children’s early experience with nouns referring to solid objects, in turn, privileges the property of shape, leading to an inductive bias, such that as children learn more nouns, they should be more likely to pick up on shape as an organizing regularity of the lexicon.
However, direct examination of this statistical regularity hypothesis in the current meta-analysis was impeded, by limited data availability on the lexical statistics and early vocabulary composition.
Another proposal is that shape bias may be guided by the syntax. In English, count nouns (e.g., "ball") are generalized by shape while mass nouns (e.g., "sand") that cannot be modified by numerals or combined with indefinite articles (‘a’ or ‘an’) are not. The presence of this distinction might facilitate English-speaking children (and other children learning languages with a mass-count distinction) in picking out the category of words to which the shape bias can be productively applied. In contrast, children learning languages that lack the mass-count distinction (e.g., some East Asian languages like Mandarin or Japanese) do not have access to this organizing principle, making the statistics of their lexicon less clear cut. Some experiments have also explicitly varied whether count/mass language is used in the presentation of new objects, directly testing whether this syntactic cue guides generalization [@samuelson2008rigid; @soja1991ontological; @soja_perception_1992]. 
It was assumed for a long time that ontology, category organization, and syntax are usually congruous with one another in the early vocabulary leading children to generalize over solid objects being always named with count nouns, and organized in categories based on shape similarity. [Samuelson and Smith 1999] examined this assumption in the MCDI corpus of early learned nouns by English-speaking children in the US. They found that "the most dominate segments of children's early noun vocabularies consist of count nouns, names for solid entities, and names for categories organized by shape. Early noun vocabularies do not include many mass nouns, names for non-solid entities, or names for categories organized by material." and that the solidity of the named object is a "better predictor of syntax and of category structure than is syntax a predictor of solidity or category structure".