Complexity in Language Acquisition

TY - JOUR

T1 - Complexity in Language Acquisition

AU - Clark, Alexander

AU - Lappin, Shalom

PY - 2013/1

Y1 - 2013/1

N2 - Learning theory has frequently been applied to language acquisition, but discussion has largely focused on information theoretic problems—in particular on the absence of direct negative evi- dence. Such arguments typically neglect the probabilistic nature of cognition and learning in gen- eral. We argue first that these arguments, and analyses based on them suffer from a major flaw: they systematically conflate the hypothesis class and the learnable concept class. As a result, they do not allow one to draw significant conclusions about the learner. Second, we claim that the real problem for language learning is the computational complexity of constructing a hypothesis from input data. Studying this problem allows for a more direct approach to the object of study—the language acquisition device—rather than the learnable class of languages, which is epiphenomenal and possibly hard to characterize. The learnability results informed by complexity studies are much more insightful. They strongly suggest that target grammars need to be objective, in the sense that the primitive elements of these grammars are based on objectively definable properties of the language itself. These considerations support the view that language acquisition proceeds primarily through data-driven learning of some form.

AB - Learning theory has frequently been applied to language acquisition, but discussion has largely focused on information theoretic problems—in particular on the absence of direct negative evi- dence. Such arguments typically neglect the probabilistic nature of cognition and learning in gen- eral. We argue first that these arguments, and analyses based on them suffer from a major flaw: they systematically conflate the hypothesis class and the learnable concept class. As a result, they do not allow one to draw significant conclusions about the learner. Second, we claim that the real problem for language learning is the computational complexity of constructing a hypothesis from input data. Studying this problem allows for a more direct approach to the object of study—the language acquisition device—rather than the learnable class of languages, which is epiphenomenal and possibly hard to characterize. The learnability results informed by complexity studies are much more insightful. They strongly suggest that target grammars need to be objective, in the sense that the primitive elements of these grammars are based on objectively definable properties of the language itself. These considerations support the view that language acquisition proceeds primarily through data-driven learning of some form.

KW - complexity, language acquiition

U2 - 10.1111/tops.12001

DO - 10.1111/tops.12001

M3 - Article

SN - 1756-8765

VL - 5

SP - 89

EP - 110

JO - Topics in Cognitive Science

JF - Topics in Cognitive Science

IS - 1

ER -