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ABSTRACT: Adult Spanish speakers generally know which form a determiner preceding a noun should have even if the noun is not in their lexicon, because Spanish demonstrates high predictability between determiner form and noun form (la noun-a and el noun-o). We asked whether young children learning Spanish are similarly sensitive to the correlation of determiner and noun forms, or whether they initially learn determiner-noun pairings one-by-one. Spanish-English bilingual children and adults repeated Spanish words and non-words preceded by gender congruous and incongruous determiners. If children learn determiner-noun pairings one-by-one, they should show a gender congruity effect only for words. In contrast with this prediction, both children and adults demonstrated congruity effects for words and non-words, indicating sensitivity to correlated morphophonological forms. Furthermore, both age groups showed more facility in producing phrases with nouns ending in -a, which are more frequent and predictable from the preceding determiner.
Journal of Child Language 12/2011; 39(4):753-76. · 1.41 Impact Factor
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ABSTRACT: Every environment contains infinite potential features and correlations among features, or patterns. Detecting valid and learnable patterns in one environment is beneficial for learners because doing so lends predictability to new environments where the same or analogous patterns recur. However, some apparent correlations among features reflect spurious patterns, and attempting to learn the latter costs time and resources with no advantage to the learner. Thus, an efficient learner in a complex environment needs to devote more attention to input that reflects a real and learnable pattern than to input that reflects a spurious or ultimately unlearnable pattern. However, in order to achieve such efficiency in the absence of external feedback, learners need to have an implicit metric of their own learning progress. Do human infants have such a metric? Data from two experiments demonstrate that 17-month-olds attend longer to learnable vs. unlearnable linguistic grammars, taking more trials to habituate and more overall time to habituate for grammars in which a valid generalization over input stimuli can be made. These data provide the first evidence that infants have an implicit metric of their own learning progress and preferentially direct their attention to learnable aspects of their environment.
Developmental Science 09/2011; 14(5):972-9. · 3.89 Impact Factor
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ABSTRACT: While many constraints on learning must be relatively experience-independent, past experience provides a rich source of guidance for subsequent learning. Discovering structure in some domain can inform a learner's future hypotheses about that domain. If a general property accounts for particular sub-patterns, a rational learner should not stipulate separate explanations for each detail without additional evidence, as the general structure has "explained away" the original evidence. In a grammar-learning experiment using tone sequences, manipulating learners' prior exposure to a tone environment affects their sensitivity to the grammar-defining feature, in this case consecutive repeated tones. Grammar-learning performance is worse if context melodies are "smooth" -- when small intervals occur more than large ones -- as Smoothness is a general property accounting for a high rate of repetition. We present an idealized Bayesian model as a "best case" benchmark for learning repetition grammars. When context melodies are Smooth, the model places greater weight on the small-interval constraint, and does not learn the repetition rule as well as when context melodies are not Smooth, paralleling the human learners. These findings support an account of abstract grammar-induction in which learners rationally assess the statistical evidence for underlying structure based on a generative model of the environment.
Cognition 01/2011; 120(3):350-9. · 3.16 Impact Factor
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ABSTRACT: The experiments here build on the widely reported finding that children are most accurate when producing phonotactic sequences with high ambient-language frequency. What remains controversial is a description of the input that children must be tracking for this effect to arise. We present a series of experiments that compare two ambient-language properties, token and type frequency, as they contribute to phonotactic learning. Token frequency is the raw number of exposures children have to a particular pattern; type frequency refers to a count of abstract entities, such as unique words. Our results suggest that children's production accuracy is most sensitive to a combination of type and token frequency: children were able to generalize a target phonotactic sequence to a new word when familiarized with multiple word-types across tokens from multiple talkers, but not when presented with either word-types with no talker variability or multiple talker-tokens of a single word.
Journal of Child Language 12/2010; 38(5):951-78. · 1.41 Impact Factor
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LouAnn Gerken
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ABSTRACT: Previous work demonstrated that 9-month-olds who were familiarized with 3-syllable strings consistent with both a broader (AAB or ABA) and narrower (AAdi or AdiA) generalization made only the latter. Because the narrower generalization is a subset of the broader one, any example that is consistent with the broader generalization but not the narrower one should allow a rational learner to select the broader generalization. The current experiment asked whether infants show evidence of being such learners. Infants who heard the stimuli that previously led to the narrower generalization plus three counterexamples mixed into the last five stimuli made the broader generalization at test. A control condition ruled out the possibility that infants based their generalization on the last five familiarization stimuli. The new findings suggest that infants effectively consider multiple competing models for their input and use rational decision criteria for selecting among these models.
Cognition 02/2010; 115(2):362-6. · 3.16 Impact Factor
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ABSTRACT: Learning must be constrained for it to lead to productive generalizations. Although biology is undoubtedly an important source of constraints, prior experience may be another, leading learners to represent input in ways that are more conducive to some generalizations than others, and/or to up- and down-weight features when entertaining generalizations. In two experiments, 4-month-old and 7-month-old infants were familiarized with sequences of musical chords or tones adhering either to an AAB pattern or an ABA pattern. In both cases, the 4-month-olds learned the generalization, but the 7-month-olds did not. The success of the 4-month-olds appears to contradict an account that this type of pattern learning is the provenance of a language-specific rule-learning module. It is not yet clear what drives the age-related change, but plausible candidates include differential experience with language and music, as well as interactions between general cognitive development and stimulus complexity.
Cognition 04/2009; 111(3):378-82. · 3.16 Impact Factor
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ABSTRACT: Children's early word production is influenced by the statistical frequency of speech sounds and combinations. Three experiments asked whether this production effect can be explained by a perceptual learning mechanism that is sensitive to word-token frequency and/or variability. Four-year-olds were exposed to nonwords that were either frequent (presented 10 times) or infrequent (presented once). When the frequent nonwords were spoken by the same talker, children showed no significant effect of perceptual frequency on production. When the frequent nonwords were spoken by different talkers, children produced them with fewer errors and shorter latencies. The results implicate token variability in perceptual learning.
Cognition 04/2009; 111(3):372-7. · 3.16 Impact Factor
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ABSTRACT: Two experiments investigated the ability of adults with a history of language-based learning disability (hLLD) and their normal language (NL) peers to learn prosodic patterns of a novel language. Participants were exposed to stimuli from an artificial language and tested on items that required generalization of the stress patterns and the hierarchical principles of stress assignment that could be inferred from the input. In Study 1, the NL group successfully generalized the patterns of stress heard during familiarization, but failed to show generalization of the hierarchical principles. The hLLD group performed at chance for both types of generalization items. In Study 2, the intensity of stress elements was increased. The performance of the NL group improved whereas the hLLD groups' performance decreased on both types of generalization items. The results indicate that NL adults are able to successfully abstract the complex hierarchical rules of stress if the prosodic cues are made sufficiently salient, but this same task is difficult for adults with hLLD. Learning outcomes: The reader will be able to understand: (1) the difference in the ability of hLLD and NL adults to process stress assignment in an implicit learning context and (2) that typical adults can abstract complex hierarchical rules of stress assignment when provided with strong cues.
Journal of Communication Disorders 03/2009; 42(5):313-23. · 1.76 Impact Factor
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ABSTRACT: Many models of learning rely on accessing internal knowledge states. Yet, although infants and young children are recognized to be proficient learners, the ability to act on metacognitive information is not thought to develop until early school years. In the experiments reported here, 3.5-year-olds demonstrated memory-monitoring skills by responding on a non-verbal task originally developed for non-human animals, in which they had to access their knowledge states. Children learned a set of paired associates, and were given the option to skip uncertain trials on a recognition memory test. Accuracy for accepted items was significantly higher than for skipped on a subsequent memory task that included all items. Additionally, children whose memory-monitoring assessments more closely matched actual memory performance showed superior overall learning, suggesting a correlation between memory-monitoring and memory itself. The results suggest that children may have implicit access to internal knowledge states at very young ages, providing an explanation for how they are able to guide learning, even as infants.
Developmental Science 10/2008; 11(5):750-60. · 3.89 Impact Factor
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ABSTRACT: An extensive body of research on child speech shows that children are sensitive to phonotactic probabilities. The general finding is that children produce native or high probability phonotactic sequences more accurately than non-native or low probability sequences (Beckman & Edwards, 1999; Edwards & Beckman, 2008; Edwards, Beckman, & Munson, 2004; Messer, 1967; Munson, 2001; Ohala, 1996; Storkel, 2001, 2003; Zamuner, Gerken, & Hammond, 2004). In one study, Zamuner et al. (2004) constructed a set of word pairs in which the final consonant of each pair member was held constant while the phonotactics of the rest of the word varied (e.g., low probability /gim/ and high probability /bom/). Children consistently produced the target final consonants more accurately when they ended high probability words. Why do children produce high probability phonotactic sequences more accurately? One answer, which relates to findings from the infant literature (e.g., Chambers, Onishi, & Fisher, 2003; Jusczyk & Aslin, 1995; Jusczyk, Luce, & Charles-Luce, 1993; Saffran & Thiessen, 2003), is that children have better internal representations of high probability sequences as a result of robust perceptual learning, what we will refer to as the perceptual learning hypothesis. This hypothesis states that the same perceptual frequency effects that have been posited by infant researchers (Jusczyk et al., 1994) to explain infants' preferential looking behavior are at least partly responsible for differences in child speech accuracy. This is in contrast to the position that children produce high probability phonotactic sequences more accurately because they say them more often, referred to hereafter as the articulatory practice hypothesis (cf. Messum, 2007). 1 The perceptual learning and articulatory practice hypotheses were recently addressed by Richtsmeier, Gerken, Goffman, and Hogan (submitted). In this study four-year-old children completed a "familiarization followed by testing" * This research was supported by NIH HD042170 to LouAnn Gerken. We gratefully acknowledge Tiffany Hogan for help with item preparation, Lauren Akif and Claire Fischer for help with transcriptions, Juliet Minton for help recruiting and running participants, and the many individuals who volunteered to serve as talkers. 1 It should be noted that the perceptual learning and articulatory practice hypotheses are not mutually exclusive. It is possible, likely even, that both perceptual and motor learning contribute to internal representations of phonological structures such as phonotactic sequences. Our purpose is to provide evidence that perceptual learning, in and of itself, contributes to the learning of phonological representations.
BUCLD, Boston; 01/2008
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ABSTRACT: Prosodic cues are used to clarify sentence structure and meaning. Two studies, one of children with specific language impairment (SLI) and one of adults with a history of learning disabilities, were designed to determine whether individuals with poor language skills recognize prosodic cues on par with their normal-language peers.
Participants were asked to determine whether low-pass filtered sentences matched unfiltered target sentences. Filtered sentences either matched the target sentence exactly or differed on between 1 and 3 parameters that affected the prosodic profile of the sentences.
Children with SLI were significantly poorer than their normal peers in determining whether low-pass filtered sentences matched or were different from unfiltered target sentences. The children's performance, measured in terms of response accuracy, deteriorated as the similarities between filtered and unfiltered sentences increased. Adults revealed a pattern of differential reaction time to sentence pairs that reflected their relative degree of similarity. There was no difference in performance accuracy for adults with a history of language/learning disabilities compared with their peers.
Given that prosodic cues are known to assist language processing, the weak prosodic skills of preschool children with SLI may limit the amount of benefit that these children derive from the presence of prosodic cues in spoken language. That the adult sample did not show a similar weakness in this skill may reflect developmental differences, sampling differences, or a combination of both.
Journal of Speech Language and Hearing Research 07/2007; 50(3):746-58. · 1.88 Impact Factor
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ABSTRACT: To assess how prosodic prominence and hierarchical foot structure influence segmental and articulatory aspects of speech production, specifically segmental accuracy and variability, and oral movement trajectory variability.
Thirty individuals participated: 10 young adults, 10 children who are normally developing, and 10 children diagnosed with specific language impairment. Segmental error and segmental variability and movement trajectory variability were compared in low and high prosodic prominence conditions (i.e., strong and weak syllables) and in different prosodic foot structures.
Between-participants findings were that both groups of children showed more segmental error and segmental variability and more movement trajectory variability than did adults. A similar within-participant pattern of results was observed for all 3 groups. Prosodic prominence influenced both segmental and motor levels of analysis, with weak syllables produced less accurately and with more lip and jaw movement trajectory variability than strong syllables. However, hierarchical foot structure affected segmental but not motor measures of speech production accuracy and variability.
Motor and segmental variables were not consistently aligned. This pattern of results has clinical implications because inferences about motor variability may not directly follow from observations of segmental variability.
Journal of Speech Language and Hearing Research 05/2007; 50(2):444-58. · 1.88 Impact Factor
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ABSTRACT: The purpose of this experiment was to determine if nonreferential morphophonological information was sufficient to facilitate the learning of gender subcategories (i.e., masculine vs. feminine) in individuals with normal language (NL) and those with a history of language-based learning disabilities (HLD).
Thirty-two adults listened for 18 min to a familiarization set of Russian words that included either 1 (single-marked) or 2 (double-marked) morphophonological markers indicating gender. Participants were then tested on their knowledge of both trained and untrained members of each gender subcategory.
Testing indicated that morphophonological information is sufficient for lexical subcategory learning in both NL and HLD groups, although the HLD group had lower overall accuracy. The HLD group benefited from double-marking relative to single-marking for subcategory learning.
The results demonstrated that learning through implicit mechanisms occurred after a relatively brief exposure to the language stimuli. In addition, the weaker overall learning by the HLD group was facilitated when multiple cues to linguistic subcategory were available in the input group members received.
Journal of Speech Language and Hearing Research 01/2007; 49(6):1257-66. · 1.88 Impact Factor
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LouAnn Gerken
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ABSTRACT: 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.
Cognition 02/2006; 98(3):B67-74. · 3.16 Impact Factor
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ABSTRACT: 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.
Journal of Child Language 06/2005; 32(2):249-68. · 1.41 Impact Factor
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LouAnn Gerken
Advances in child development and behavior 02/2005; 33:153-92. · 0.95 Impact Factor
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LouAnn Gerken
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ABSTRACT: Infants' ability to rapidly extract properties of language-like systems during brief laboratory exposures has been taken as evidence about the innate linguistic state of humans. However, previous studies have focused on structural properties that are not central to descriptions of natural language. In the current study, infants were exposed to 3- and 5-syllable words from one of the two artificial languages that employed the same stress assignment constraints found in natural languages. Infants were able to generalize beyond the stress patterns encountered during familiarization to new patterns reflecting the same constraints. The results suggest that infants are able to rapidly extract the types of structural information required for human language.
Cognition 11/2004; 93(3):B89-96. · 3.16 Impact Factor
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ABSTRACT: When English-speaking two-year-olds begin producing polysyllabic words, they often omit unstressed syllables that precede syllables with primary stress (Allen & Hawkins, 1980; Klein, 1981; Gerken, 1994a). One proposed mechanism for these omissions is that children omit syllables at a phonological level, due to prosodic constraints that act on outputs. Under such accounts, it has been largely assumed that these syllables are simply missing, or deleted, from children's outputs. The present research consists of a pair of experiments that tested this assumption by investigating the acoustic properties of utterances manifesting or lacking weak initial syllable omissions. In the two experiments, 33 two-year-old children were asked to imitate sentences like 'He kissed Lucinda' (often reduced as expected to a disyllabic trochaic form, e.g. 'He kissed _cinda') and 'He kissed Cindy'. Durations of each child's imitations were measured from the onset of the verb to the onset of the name, for each pair of sentences containing the reduced or unreduced disyllabic forms, for example, 'kissed cinda' vs. 'kissed Cindy'. Our results yielded a significantly longer duration for the verb-onset to name-onset portion of sentences containing reduced '_cinda'-type names than for sentences with 'Cindy'-type names. This finding provides evidence that children do not completely delete weak syllables. Rather, the data from the phonetic analysis indicate that some prosodic trace exists of the omitted syllable.
Journal of Child Language 09/2004; 31(3):561-86. · 1.41 Impact Factor
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ABSTRACT: For nearly two decades it has been known that infants' perception of speech sounds is affected by native language input during the first year of life. However, definitive evidence of a mechanism to explain these developmental changes in speech perception has remained elusive. The present study provides the first evidence for such a mechanism, showing that the statistical distribution of phonetic variation in the speech signal influences whether 6- and 8-month-old infants discriminate a pair of speech sounds. We familiarized infants with speech sounds from a phonetic continuum, exhibiting either a bimodal or unimodal frequency distribution. During the test phase, only infants in the bimodal condition discriminated tokens from the endpoints of the continuum. These results demonstrate that infants are sensitive to the statistical distribution of speech sounds in the input language, and that this sensitivity influences speech perception. q 2002 Elsevier Science B.V. All rights reserved.
02/2003;
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ABSTRACT: For nearly two decades it has been known that infants' perception of speech sounds is affected by native language input during the first year of life. However, definitive evidence of a mechanism to explain these developmental changes in speech perception has remained elusive. The present study provides the first evidence for such a mechanism, showing that the statistical distribution of phonetic variation in the speech signal influences whether 6- and 8-month-old infants discriminate a pair of speech sounds. We familiarized infants with speech sounds from a phonetic continuum, exhibiting either a bimodal or unimodal frequency distribution. During the test phase, only infants in the bimodal condition discriminated tokens from the endpoints of the continuum. These results demonstrate that infants are sensitive to the statistical distribution of speech sounds in the input language, and that this sensitivity influences speech perception.
Cognition 02/2002; 82(3):B101-11. · 3.16 Impact Factor
