Poverty of the stimulus

Poverty of the stimulus arguments are used as evidence for universal grammar, the notion that at least some aspects of linguistic competence are innate.

[2] Plato's Problem directly parallels the idea of the innateness of language, universal grammar, and more specifically the poverty of the stimulus argument because it reveals that people's knowledge is richer than what they are exposed to.

[4][5][6] Pullum and Scholz frame the poverty of the stimulus argument by examining all of the ways that the input is insufficient for language acquisition.

[9] Degeneracy of scope means that the input does not contain information about the full extent of any grammatical rules.

Degeneracy of quality means that children are exposed to speech errors, utterances by nonnative speakers, and false starts, potentially obscuring the grammatical structure of the language.

[10] From the nativists' point of view, the insufficiency of the input leads to the conclusion that humans are hard-wired with a UG and thus support the innateness hypothesis.

[11] For example, Fiona Cowie claims that the Poverty of Stimulus argument fails "on both empirical and conceptual grounds to support nativism".

Given that speech to children does not indicate what interpretations are impossible, the input is equally consistent with a grammar that allows coreference between "he" and "the Ninja Turtle" in (2) and one that does not.

However, even if a speaker intends (2) in this way, it would be difficult to distinguish that interpretation from one in which "one" simply meant "ball".

Because questions with islands are ungrammatical, they are not included in the speech that children hear—but neither are grammatical Wh-questions that span multiple clauses.

Halle (1978)[15] argues that the morphophonological rule governing the English plural produces forms that are consistent with two grammars.

These rules are exactly equal in their coverage of English since the set of consonants that triggers the [s] pronunciation is identical in the two cases.

Since there is "no indication" that speakers could have acquired this knowledge, Halle argues that the tendency to build rules in terms of natural classes comes from a factor internal to the child and not from their experience.

For example, in learning the word "dog", a child might see a German Shepherd, a Great Dane and a Poodle.

For example Lila Gleitman poses a POS argument with respect to verbs that label mental states.

Thus, our ability to learn these word meanings must be shaped by factors internal to the child and not simply from the conditions of their use.

[16] The empirical basis of poverty of the stimulus arguments has been challenged by Geoffrey Pullum and others, leading to back-and-forth debate in the language acquisition literature.

[17][18] Recent work has also suggested that some recurrent neural network architectures are able to learn hierarchical structure without an explicit constraint.