The link between statistical segmentation and word learning in adults

Many studies have shown that listeners can segment words from running speech based on conditional probabilities of syllable transitions, suggesting that this statistical learning could be a foundational component of language learning. However, few studies have shown a direct link between statistical segmentation and word learning. We examined this possible link in adults by following a statistical segmentation exposure phase with an artificial lexicon learning phase. Participants were able to learn all novel object-label pairings, but pairings were learned faster when labels contained high probability (word-like) or non-occurring syllable transitions from the statistical segmentation phase than when they contained low probability (boundary-straddling) syllable transitions. This suggests that, for adults, labels inconsistent with expectations based on statistical learning are harder to learn than consistent or neutral labels. In contrast, a previous study found that infants learn consistent labels, but not inconsistent or neutral labels.     

Fine-grained sensitivity to statistical information in adult word learning

A language learner trying to acquire a new word must often sift through many potential relations between particular words and their possible meanings. In principle, statistical information about the distribution of those mappings could serve as one important source of data, but little is known about whether learners can in fact track multiple word-referent mappings, and, if they do, the precision with which they can represent those statistics. To test this, two experiments contrasted a pair of possibilities: that learners encode the fine-grained statistics of mappings in the input - both high- and low-frequency mappings - or, alternatively, that only high frequency mappings are represented. Participants were briefly trained on novel word-novel object pairs combined with varying frequencies: some objects were paired with one word, other objects with multiple words with differing frequencies (ranging from 10% to 80%). Results showed that participants were exquisitely sensitive to very small statistical differences in mappings. The second experiment showed that word learners' representation of low frequency mappings is modulated as a function of the variability in the environment. Implications for Mutual Exclusivity and Bayesian accounts of word learning are discussed.     

Social cues modulate the representations underlying cross-situational learning

Because children hear language in environments that contain many things to talk about, learning the meaning of even the simplest word requires making inferences under uncertainty. A cross-situational statistical learner can aggregate across naming events to form stable word-referent mappings, but this approach neglects an important source of information that can reduce referential uncertainty: social cues from speakers (e.g., eye gaze). In four large-scale experiments with adults, we tested the effects of varying referential uncertainty in cross-situational word learning using social cues. Social cues shifted learners away from tracking multiple hypotheses and towards storing only a single hypothesis (Experiments 1 and 2). In addition, learners were sensitive to graded changes in the strength of a social cue, and when it became less reliable, they were more likely to store multiple hypotheses (Experiment 3). Finally, learners stored fewer word-referent mappings in the presence of a social cue even when given the opportunity to visually inspect the objects for the same amount of time (Experiment 4). Taken together, our data suggest that the representations underlying cross-situational word learning of concrete object labels are quite flexible: In conditions of greater uncertainty, learners store a broader range of information.     

Word learning is 'smart': evidence that conceptual information affects preschoolers' extension of novel words

We examined electrophysiological correlates of conscious change detection versus change blindness for equivalent displays. Observers had to detect any changes, across a visual interruption, between a pair of successive displays. Each display comprised grey circles on a background of alternate black and white stripes. Foreground changes arose when light-grey circles turned dark-grey and vice-versa. Physically stronger background changes arose when all black stripes turned white and vice-versa. Despite their physical strength, background changes were undetected unless attention was directed to them, whereas foreground changes were invariably seen. Event-related potentials revealed that the P300 component was suppressed for unseen background changes, as compared with the same changes when seen. This effect arose first over frontal sites, and then spread to parietal sites. These results extend recent fMRI findings that fronto-parietal activation is associated with conscious visual change detection, to reveal the timing of these neural correlates.     

Acquiring variation in an artificial language: Children and adults are sensitive to socially conditioned linguistic variation

Languages exhibit sociolinguistic variation, such that adult native speakers condition the usage of linguistic variants on social context, gender, and ethnicity, among other cues. While the existence of this kind of socially conditioned variation is well-established, less is known about how it is acquired. Studies of naturalistic language use by children provide various examples where children’s production of sociolinguistic variants appears to be conditioned on similar factors to adults’ production, but it is difficult to determine whether this reflects knowledge of sociolinguistic conditioning or systematic differences in the input to children from different social groups. Furthermore, artificial language learning experiments have shown that children have a tendency to eliminate variation, a process which could potentially work against their acquisition of sociolinguistic variation. The current study used a semi-artificial language learning paradigm to investigate learning of the sociolinguistic cue of speaker identity in 6-year-olds and adults. Participants were trained and tested on an artificial language where nouns were obligatorily followed by one of two meaningless particles and were produced by one of two speakers (one male, one female). Particle usage was conditioned deterministically on speaker identity (Experiment 1), probabilistically (Experiment 2), or not at all (Experiment 3). Participants were given tests of production and comprehension. In Experiments 1 and 2, both children and adults successfully acquired the speaker identity cue, although the effect was stronger for adults and in Experiment 1. In addition, in all three experiments, there was evidence of regularization in participants’ productions, although the type of regularization differed with age: children showed regularization by boosting the frequency of one particle at the expense of the other, while adults regularized by conditioning particle usage on lexical items. Overall, results demonstrate that children and adults are sensitive to speaker identity cues, an ability which is fundamental to tracking sociolinguistic variation, and that children’s well-established tendency to regularize does not prevent them from learning sociolinguistically conditioned variation.     

Phonological recoding and rapid orthographic learning in third-graders' silent reading: a critical test of the self-teaching hypothesis

This study examined rapid orthographic learning following silent reading in third-grade children as a function of number of target nonword repetitions and test delay. In each of two test sessions at least 6 days apart, children read a series of short stories, with each story containing a different nonword repeated either four or eight times. In the second session, after the stories had been read, children were asked to read short lists of target nonwords or homophonic alternatives. Children read target nonwords faster than homophones, indicating that they had formed functional orthographic representations of the target nonwords through phonologically recoding them during silent story reading. They also preferred target nonwords to homophones in an orthographic choice task in which the alternatives included the target, the homophone, and a visually similar foil, although here orthographic learning was stronger for items encountered eight times within stories and stronger for items tested immediately. These findings provide critical evidence in support of Share's self-teaching through phonological recoding hypothesis.     

In search of a science‐based application: A learning tool for reading acquisition

This is a story about the fate of a psychological application: from its conception to the optimistic vision surrounding its future. We hope that this application – an enjoyable learning game (www or mobile phone‐based, available free of charge to the end users) for children – can at best help millions of children in their reading acquisition in the future. Its basis was created by following intensively the development of children with (N = 107) and without (N = 92) genetic (familial) risk for dyslexia from birth to puberty in the Jyväskylä Longitudinal study of Dyslexia (JLD)‐project. We summarize some of the major findings of the JLD in order to facilitate understanding of the reasons and logic behind the development of the game. Originally intended as a research tool for reading acquisition, its potential for prevention of reading difficulties was quickly recognized.     

The relationship between knowing a word and reading it aloud in children’s word reading development

This experiment examined the item-level relationship between 7-year-olds’ ability to read words aloud and their knowledge of the same words in the oral domain. Two types of knowledge were contrasted: familiarity with the phonological form of the word (lexical phonology), measured by auditory lexical decision, and semantic knowledge, measured by a definitions task. Overall, there was a robust relationship between word knowledge and reading aloud success. The association was stronger when words contained irregular spelling-sound correspondences. There was no evidence that a deeper or more semantic knowledge of words was more closely related to reading aloud success beyond the association between reading success and familiarity with the phonological form of the same words. This finding is not compatible with models that see semantics as contributing directly to the reading aloud process, at least during the relatively early stages of reading development. More critical was whether or not a word was considered a lexical item, as indexed by auditory lexical decision performance.     

Orthographic learning during reading: examining the role of self-teaching

Thirty-four second grade children read target homophonic pseudowords (e.g., slurst/slirst) in the context of real stories in a test of the self-teaching theory of early reading acquisition. The degree of orthographic learning was assessed with three converging tasks: homophonic choice, spelling, and target naming. Each of the tasks indicated that orthographic learning had taken place because processing of target homophones (e.g., yait) was superior to that of their homophonic controls (e.g., yate). Consistent with the self-teaching hypothesis, we obtained a substantial correlation (r=.52) between orthographic learning and the number of target homophones correctly decoded during story reading. Hierarchical multiple regression analyses indicated that neither RAN tasks nor general cognitive ability predicted variance in orthographic learning once the number of target homophones correctly decoded during story reading had been partialed out. In contrast, a measure of orthographic knowledge predicted variance in orthographic learning once the number of targets correctly decoded had been partialed. The development of orthographic knowledge appears to be not entirely parasitic on decoding ability. (c) 2002 Elsevier Science (USA).     

Statistically Induced Chunking Recall: A Memory-Based Approach to Statistical Learning

The computations involved in statistical learning have long been debated. Here, we build on work suggesting that a basic memory process, chunking, may account for the processing of statistical regularities into larger units. Drawing on methods from the memory literature, we developed a novel paradigm to test statistical learning by leveraging a robust phenomenon observed in serial recall tasks: that short-term memory is fundamentally shaped by long-term distributional learning. In the statistically induced chunking recall (SICR) task, participants are exposed to an artificial language, using a standard statistical learning exposure phase. Afterward, they recall strings of syllables that either follow the statistics of the artificial language or comprise the same syllables presented in a random order. We hypothesized that if individuals had chunked the artificial language into word-like units, then the statistically structured items would be more accurately recalled relative to the random controls. Our results demonstrate that SICR effectively captures learning in both the auditory and visual modalities, with participants displaying significantly improved recall of the statistically structured items, and even recall specific trigram chunks from the input. SICR also exhibits greater test–retest reliability in the auditory modality and sensitivity to individual differences in both modalities than the standard two-alternative forced-choice task. These results thereby provide key empirical support to the chunking account of statistical learning and contribute a valuable new tool to the literature.     

Modeling Statistical Insensitivity: Sources of Suboptimal Behavior

Children acquiring languages with noun classes (grammatical gender) have ample statistical information available that characterizes the distribution of nouns into these classes, but their use of this information to classify novel nouns differs from the predictions made by an optimal Bayesian classifier. We use rational analysis to investigate the hypothesis that children are classifying nouns optimally with respect to a distribution that does not match the surface distribution of statistical features in their input. We propose three ways in which children's apparent statistical insensitivity might arise, and find that all three provide ways to account for the difference between children's behavior and the optimal classifier. A fourth model combines two of these proposals and finds that children's insensitivity is best modeled as a bias to ignore certain features during classification, rather than an inability to encode those features during learning. These results provide insight into children's developing knowledge of noun classes and highlight the complex ways in which statistical information from the input interacts with children's learning processes.     

Idiomatic syntactic constructions and language learning

This article explores the influence of idiomatic syntactic constructions (i.e., constructions whose phrase structure rules violate the rules that underlie the construction of other kinds of sentences in the language) on the acquisition of phrase structure. In Experiment 1, participants were trained on an artificial language generated from hierarchical phrase structure rules. Some participants were given exposure to an idiomatic construction (IC) during training, whereas others were not. Under some circumstances, the presence of an idiomatic construction in the input aided learners in acquiring the phrase structure of the language. Experiment 2 provides a replication of the first experiment and extends the findings by showing that idiomatic constructions that strongly violate the predictive dependencies that define the phrase structure of the language do not aid learners in acquiring the structure of the language. Together, our data suggest that (a) idiomatic constructions aid learners in acquiring the phrase structure of a language by highlighting relevant structural elements in the language, and (b) such constructions are useful cues to learning to the extent that learners can keep their knowledge of the idiomatic construction separate from their knowledge of the rest of the language.     

Competitive Processes in Cross‐Situational Word Learning

Cross‐situational word learning, like any statistical learning problem, involves tracking the regularities in the environment. However, the information that learners pick up from these regularities is dependent on their learning mechanism. This article investigates the role of one type of mechanism in statistical word learning: competition. Competitive mechanisms would allow learners to find the signal in noisy input and would help to explain the speed with which learners succeed in statistical learning tasks. Because cross‐situational word learning provides information at multiple scales—both within and across trials/situations—learners could implement competition at either or both of these scales. A series of four experiments demonstrate that cross‐situational learning involves competition at both levels of scale, and that these mechanisms interact to support rapid learning. The impact of both of these mechanisms is considered from the perspective of a process‐level understanding of cross‐situational learning.     

Imitation is beneficial for verb learning in toddlers

The interplay between action and language is still not fully understood in terms of its relevance for early language development. Here, we investigated whether action imitation may be beneficial for first language acquisition. In a word-learning study 24-, 30- and 36-month-old children (N = 96) learned the labels of different actions in one of two conditions: Either the children just observed the experimenter producing the action (observation condition) or children produced the action themselves (action condition). The results show that 36-month-olds learned the labels of the more complex actions in both conditions, whereas 30-month-olds learned the labels only in the action but not in the observation condition. These findings suggest that action imitation is beneficial for verb learning early in life.     

Word learning and phonetic processing in preschool-age children

Consonants and vowels have been shown to play different relative roles in different processes, including retrieving known words from pseudowords during adulthood or simultaneously learning two phonetically similar pseudowords during infancy or toddlerhood. The current study explores the extent to which French-speaking 3- to 5-year-olds exhibit a so-called “consonant bias” in a task simulating word acquisition, that is, when learning new words for unfamiliar objects. In Experiment 1, the to-be-learned words differed both by a consonant and a vowel (e.g., /byf/-/duf/), and children needed to choose which of the two objects to associate with a third one whose name differed from both objects by either a consonant or a vowel (e.g., /dyf/). In such a conflict condition, children needed to favor (or neglect) either consonant information or vowel information. The results show that only 3-year-olds preferentially chose the consonant identity, thereby neglecting the vowel change. The older children (and adults) did not exhibit any response bias. In Experiment 2, children needed to pick up one of two objects whose names differed on either consonant information or vowel information. Whereas 3-year-olds performed better with pairs of pseudowords contrasting on consonants, the pattern of asymmetry was reversed in 4-year-olds, and 5-year-olds did not exhibit any significant response bias. Interestingly, girls showed overall better performance and exhibited earlier changes in performance than boys. The changes in consonant/vowel asymmetry in preschoolers are discussed in relation with developments in linguistic (lexical and morphosyntactic) and cognitive processing.     

Exclusion constraints facilitate statistical word learning

The roles of linguistic, cognitive, and social-pragmatic processes in word learning are well established. If statistical mechanisms also contribute to word learning, they must interact with these processes; however, there exists little evidence for such mechanistic synergy. Adults use co-occurrence statistics to encode speech-object pairings with detailed sensitivity in stochastic learning environments (Vouloumanos, 2008). Here, we replicate this statistical work with nonspeech sounds and compare the results with the previous speech studies to examine whether exclusion constraints contribute equally to the statistical learning of speech-object and nonspeech-object associations. In environments in which performance could benefit from exclusion, we find a learning advantage for speech over nonspeech, revealing an interaction between statistical and exclusion processes in associative word learning.     

Lexical competition in young children's word learning

In two experiments, 1.5-year-olds were taught novel words whose sound patterns were phonologically similar to familiar words (novel neighbors) or were not (novel nonneighbors). Learning was tested using a picture-fixation task. In both experiments, children learned the novel nonneighbors but not the novel neighbors. In addition, exposure to the novel neighbors impaired recognition performance on familiar neighbors. Finally, children did not spontaneously use phonological differences to infer that a novel word referred to a novel object. Thus, lexical competition--inhibitory interaction among words in speech comprehension--can prevent children from using their full phonological sensitivity in judging words as novel. These results suggest that word learning in young children, as in adults, relies not only on the discrimination and identification of phonetic categories, but also on evaluating the likelihood that an utterance conveys a new word.     

Stimulus modality and working memory performance in Greek children with reading disabilities: Additional evidence for the pictorial superiority hypothesis

This study investigated the effects of stimulus presentation modality on working memory performance in children with reading disabilities (RD) and in typically developing children (TDC), all native speakers of Greek. It was hypothesized that the visual presentation of common objects would result in improved learning and recall performance as compared to the auditory presentation of stimuli. Twenty children, ages 10–12, diagnosed with RD were matched to 20 TDC age peers. The experimental tasks implemented a multitrial verbal learning paradigm incorporating three modalities: auditory, visual, and auditory plus visual. Significant group differences were noted on language, verbal and nonverbal memory, and measures of executive abilities. A mixed-model MANOVA indicated that children with RD had a slower learning curve and recalled fewer words than TDC across experimental modalities. Both groups of participants benefited from the visual presentation of objects; however, children with RD showed the greatest gains during this condition. In conclusion, working memory for common verbal items is impaired in children with RD; however, performance can be facilitated, and learning efficiency maximized, when information is presented visually. The results provide further evidence for the pictorial superiority hypothesis and the theory that pictorial presentation of verbal stimuli is adequate for dual coding.     

Reading ability is negatively related to Stroop interference

Stroop interference is often taken as evidence for reading automaticity even though young and poor readers, who presumably lack reading automaticity, present strong interference. Here the relationship between reading skills and Stroop interference was studied in a 7th-grade sample. Greater interference was observed in children diagnosed with reading disability (dyslexia) than in unimpaired children. Moreover, poorer reading skills were found to correlate with greater Stroop interference in the general school population. In correlation and regression analyses, interference was primarily associated with reading speed, with an additional unique contribution of reading accuracy. Color naming errors were few and not comparably related to reading skills. The relation of reading skill to Stroop interference was examined in computational modeling simulations. The production model of Roelofs [Roelofs, A. (2003). Goal-referenced selection of verbal action: modeling attentional control in the Stroop task. Psychological Review, 110, 88-125], in which interference is primarily due to word stimuli having direct access to word form encoding whereas color naming must pass through concept activation and lemma selection, was found to account well for the human data after imposing covariation constraints on parameters controlling word processing and blocking latency, in modifications not affecting the model's previous fit to other data. The connectionist model of Cohen, Dunbar, and McClelland [Cohen, J. D., Dunbar, K., & McClelland, J. L. (1990). On the control of automatic processes: a parallel distributed processing account of the Stroop effect. Psychological Review, 97, 332-361], in which interference is caused by differential route strength, implementing an automaticity account, approximated the observed patterns with network-wide parameter manipulations not specific to reading, such as processing speed and response threshold, likely to affect previously optimized performance. On the basis of the empirical and modeling data we argue for a direct link between reading skill and interference, beyond the effects of executive functioning.     

Orthographic learning via self-teaching in children learning to read English: effects of exposure, durability, and context

This experiment investigated orthographic learning via self-teaching in 8- and 9-year-olds learning to read English. Children were exposed to novel words, and following a 1- or 7-day delay interval, orthographic learning was assessed by asking children to select previously seen novel words from an array of visually and phonologically similar foils. Novel words were exposed either in meaningful text or in isolation, and number of exposures was manipulated with each novel word appearing once, twice, or four times. Learning increased as a function of number of exposures, although some evidence of durable one-trial learning was observed. Context played no role, suggesting that orthographic learning is not dependent on meaning-based information. In general, these findings offer support for the central aspects of Share's self-teaching hypothesis. However, although we observed a general relation between phonological decoding and orthographic learning, the relation did not hold at an item-by-item level of analysis, suggesting that a strong version of Share's item-based account is not correct.