Children Use Statistics and Semantics in the Retreat from Overgeneralization

How do children learn to restrict their productivity and avoid ungrammatical utterances? The present study addresses this question by examining why some verbs are used with un- prefixation (e.g., unwrap) and others are not (e.g., *unsqueeze). Experiment 1 used a priming methodology to examine children's (3–4; 5–6) grammatical restrictions on verbal un- prefixation. To elicit production of un-prefixed verbs, test trials were preceded by a prime sentence, which described reversal actions with grammatical un- prefixed verbs (e.g., Marge folded her arms and then she unfolded them). Children then completed target sentences by describing cartoon reversal actions corresponding to (potentially) un- prefixed verbs. The younger age-group's production probability of verbs in un- form was negatively related to the frequency of the target verb in bare form (e.g., squeez/e/ed/es/ing), while the production probability of verbs in un- form for both age groups was negatively predicted by the frequency of synonyms to a verb's un- form (e.g., release/*unsqueeze). In Experiment 2, the same children rated the grammaticality of all verbs in un- form. The older age-group's grammaticality judgments were (a) positively predicted by the extent to which each verb was semantically consistent with a semantic “cryptotype” of meanings - where “cryptotype” refers to a covert category of overlapping, probabilistic meanings that are difficult to access - hypothesised to be shared by verbs which take un-, and (b) negatively predicted by the frequency of synonyms to a verb's un- form. Taken together, these experiments demonstrate that children as young as 4;0 employ pre-emption and entrenchment to restrict generalizations, and that use of a semantic cryptotype to guide judgments of overgeneralizations is also evident by age 6;0. Thus, even early developmental accounts of children's restriction of productivity must encompass a mechanism in which a verb's semantic and statistical properties interact

Pronoun co-referencing errors::Challenges for generativist and usage-based accounts

This study tests accounts of co-reference errors whereby children allow ‘‘Mama Bear’ ’ and ‘‘her’ ’ to co-refer in sentences like ‘‘Mama Bear is washing her’ ’ (Chien and Wexler 1990). 63 children aged 4;6, 5;6 and 6;6 participated in a truth-value judgment task augmented with a sentence pro-duction component. There were three major finding: 1) contrary to predic-tions of most generativist accounts, children accepted co-reference even in cases of bound anaphora e.g., ‘‘Every girl is washing her’ ’ 2) contrary to Thornton and Wexler (1999), errors did not appear to occur because chil-dren understood referring expressions to be denoting the same person in dif-ferent guises 3) contrary to usage-based accounts, errors were less likely in sentences that contained lower as opposed to higher frequency verbs. Error rates also di¤ered significantly according to pronoun type (‘‘him’’, ‘‘her’’, ‘‘them’’). These challenging results are discussed in terms of possible pro-cessing explanations