Poverty of the Stimulus? A Rational Approach

The Poverty of the Stimulus (PoS) argument holds that children do not receive enough evidence to infer the existence of core aspects of language, such as the dependence of linguistic rules on hierarchical phrase structure. We reevaluate one version of this argument with a Bayesian model of grammar induction, and show that a rational learner without any initial language-specific biases could learn this dependency given typical child-directed input. This choice enables the learner to master aspects of syntax, such as the auxiliary fronting rule in interrogative formation, even without having heard directly relevant data (e.g., interrogatives containing an auxiliary in a relative clause in the subject NP).