LouAnn Gerken

Artificial Grammar Learning by 1-Year-Olds Leads to Specific and Abstract Knowledge.

Four experiments used the head-turn preference procedure to assess whether infants could extract and remember information from auditory strings produced by a miniature artificial grammar. In all four experiments, infants generalized to new structure by discriminating new grammatical strings from ungrammatical ones after less than 2 min exposure to the grammar. Infants acquired specific information about the grammar as demonstrated by the ability to discriminate new grammatical strings from those with illegal endpoints (Experiment 1). Infants also discriminated new grammatical strings from those with string-internal pairwise violations (Experiments 2 and 3). Infants in Experiment 4 abstracted beyond specific word order as demonstrated by the ability to discriminate new strings produced by their training grammar from strings produced by another grammar despite a change in vocabulary between training and test. We discuss the implications of these findings for the study of language acquisition.

Infant artificial language learning and language acquisition

The rapidity with which children acquire language is one of the mysteries of human cognition. A view held widely for the past 30 years is that children master language by means of a language-specific learning device. An earlier proposal, which has generated renewed interest, is that children make use of domain-general, associative learning mechanisms. However, our current lack of knowledge of the actual learning mechanisms involved during infancy makes it difficult to determine the relative contributions of innate and acquired knowledge. A recent approach to studying this problem exposes infants to artificial languages and assesses the resulting learning. In this article, we review studies using this paradigm that have led to a number of exciting discoveries regarding the learning mechanisms available during infancy. These studies raise important issues with respect to whether such mechanisms are general or specific to language, the extent to which they reflect statistical learning versus symbol manipulation, and the extent to which such mechanisms change with development. The fine-grained characterizations of infant learning mechanisms that this approach permits should result in a better understanding of the relative contributions of, and the dynamic between, innate and learned factors in language acquisition.

The head-turn preference procedure for testing auditory perception

Abstract The Head-Turn Preference Procedure (HPP) is valuable for testing perception of sustained auditory materials, particularly speech. This article presents a detailed description of the current version of HPP, new evidence of the objectivity of measurements within it, and an account of recent modifications.

The metrical basis for children's subjectless sentences

Abstract Young English speakers often omit sentential subjects but infrequently omit objects. In this paper I consider five accounts for these omissions that differ in the explanation of why children make omissions (grammar versus production constraints) and what causes the asymmetry in subject and object omissions. Hyams (1986, Language acquisition and the theory of parameters , Dordrecht, Reidel; 1987 , Paper presented at the Boston University Conference on Language Development, October) proposes that children are born with an innate grammar that causes them to omit pronominal subjects. Valian (1989 , Papers and Reports on Child Language Development , 28 , 156–163) notes that subject deletion is acceptable in casual adult English: Based on these data, children omit subjects when sentence complexity puts too great a burden on the production system. On a pragmatic account ( Bates, 1976 , Language and context . New York: Academic Press; Greenfield & Smith, 1976 , The structure of communication in early language development . New York: Academic Press), children have limited production abilities and omit the least communicatively informative elements: Because subjects typically contain given information, they are frequently omitted. P. Bloom (1989 , Papers and Reports on Child Language Development , 28 , 57–63) argues that processing considerations cause children to expand sentences rightward, at the expense of leftward elements. Finally, I propose a metrical hypothesis in which children omit weakly stressed syllables, including pronouns and other function morphemes, particularly from iambic (weak-strong) feet. Data from an imitation task strongly support the metrical hypothesis over the others. The results are examined in light of a model of developing speech production.

Infants can use distributional cues to form syntactic categories.

Nearly all theories of language development emphasize the importance of distributional cues for segregating words and phrases into syntactic categories like noun, feminine or verb phrase. However, questions concerning whether such cues can be used to the exclusion of referential cues have been debated. Using the headturn preference procedure, American children aged 1;5 were briefly familiarized with a partial Russian gender paradigm, with a subset of the paradigm members withheld. During test, infants listened on alternate trials to previously withheld grammatical items and ungrammatical items with incorrect gender markings on previously heard stems. Across three experiments, infants discriminated new grammatical from ungrammatical items, but like adults in previous studies, were only able to do so when a subset of familiarization items was double marked for gender category. The results suggest that learners can use distributional cues to category structure, to the exclusion of referential cues, from relatively early in the language learning process.

A metrical template account of children's weak syllable omissions from multisyllabic words.

Young children learning English as well as many other languages frequently omit weakly stressed syllables from multisyllabic words. In particular, they are more likely to omit weak syllables from word-initial positions than from word-internal or -final positions. For example, the weak syllable of a weak-strong (WS) word like giraffe is much more likely to be omitted than the weak syllable of a SW word like tiger. Three hypotheses for this omission pattern have been offered. In two, childrens weak syllable omissions reflect innate perceptual biases either to ignore initial weak syllables or to encode word-final syllables. In contrast, the SW Production Template Hypothesis states that children have a template for producing a strong syllable followed by an optional weak syllable. When they apply a series of SW templates to their intended utterances, weak syllables that do not fit the templates are more likely to be omitted than those that do. To compare the three hypotheses, young two-year-olds were asked to say four-syllable SWWS and WSWS nonsense words. Childrens pattern of weak syllable preservations was highly consistent with the SW production template hypothesis, but not with the perception-based hypotheses. Implications of this research for childrens function morpheme omissions and for the relation of metrical and segmental production templates are discussed.

When prosody fails to cue syntactic structure: 9-month-olds' sensitivity to phonological versus syntactic phrases ☆

According to prosodic bootstrapping accounts of syntax acquisition, language learners use the correlation between syntactic boundaries and prosodic changes (e.g., pausing, vowel lengthening, large increases or decreases in fundamental frequency) to cue the presence and arrangement of syntactic constituents. However, recent linguistic accounts suggest that prosody does not directly reflect syntactic structure but rather is governed by independent prosodic units such as phonological phrases. To examine the implications of this view for the prosodic bootstrapping hypothesis, infants in Experiment 1 were presented with sentences in which pauses were inserted either between the subject noun phrase (NP) and verb or after the verb. Half of the infants heard sentences with lexical NP subjects, in which prosodic structure is consistent with syntactic structure. The other half heard sentences with pronoun subjects, in which prosodic structure does not mirror syntactic structure. In a preferential listening paradigm, infants in the lexical NP condition listened longer to materials containing pauses between the subject and verb, the main syntactic constituents. However, in the pronoun NP condition, infants showed no difference in listening times for the two pause locations. To determine if other sentence types containing pronoun subjects potentially provide information about the syntactic constituency of these elements, infants in Experiment 2 heard yes-no questions with pronoun subjects, in which the prosodic structure reflects the constituency of the subject. Infants listened longer when pauses were inserted between the subject and verb than after the verb. Taken together, our results suggest that the prosodic information in an individual sentence is not always sufficient to assign a syntactic structure. Rather, learners must engage in active inferential processes, using cross-sentence comparisons and other types of information to arrive at the correct syntactic representation.

Decisions, decisions: infant language learning when multiple generalizations are possible

Two experiments presented infants with artificial language input in which at least two generalizations were logically possible. The results demonstrate that infants made one of the two generalizations tested, the one that was most statistically consistent with the particular subset of the data they received. The experiments shed light on how learners might go about solving the induction problem for human language.

Sensitivity to word order cues by normal and language/learning disabled adults.

UNLABELLED Sixteen adults with language/learning disabilities (L/LD) and 16 adults who lacked a personal or familial history of L/LD participated in a study designed to test sensitivity to word order cues that signaled grammatical versus ungrammatical word strings belonging to an artificial grammar. In an exposure phase, participants heard word strings constructed of novel CVC words for a period of 5 min. In a test phase, participants were asked to judge new sentences as either obeying or violating the rules of the grammar they heard. L/LD participants performed significantly below the comparison group on this task. The results suggest that this skill, which emerges early in life for normal children, is problematic for adults with L/LD. LEARNING OUTCOMES The reader will become familiar with a paradigm that allows assessment of rapid learning of word order rules and how this learning differs for normal and language/learning disabled adults.

The basis of transfer in artificial grammar learning

In two experiments, we examined the extent to which knowledge of sequential dependencies and/or patterns of repeating elements is used during transfer in artificial grammar learning. According to one view of transfer, learners abstract the grammar’s sequential dependencies and then learn a mapping to new vocabulary at test (Dienes, Altmann, & Gao, 1999). Elements that are repeated have no special status on this view, and so a logical prediction is that learners should transfer as well after exposure to a grammar without repetitions as after exposure to a grammar with them. On another view, repetition structure is the very basis of transfer (Brooks & Vokey, 1991; Mathews & Roussel, 1997). Learners were trained on grammars with or without repeating elements to test these competing views. Learners demonstrated considerable knowledge of sequential dependencies in their training vocabulary but did not use such knowledge to transfer to a new vocabulary. Transfer only occurred in the presence of repetition structure, demonstrating this to be the basis of transfer.