A Multiple‐Channel Model of Task‐Dependent Ambiguity Resolution in Sentence Comprehension

Traxler, Pickering, and Clifton (1998) found that ambiguous sentences are read faster than their unambiguous counterparts. This so‐called ambiguity advantage has presented a major challenge to classical theories of human sentence comprehension (parsing) because its most prominent explanation, in the form of the unrestricted race model (URM), assumes that parsing is non‐deterministic. Recently, Swets, Desmet, Clifton, and Ferreira (2008) have challenged the URM. They argue that readers strategically underspecify the representation of ambiguous sentences to save time, unless disambiguation is required by task demands. When disambiguation is required, however, readers assign sentences full structure—and Swets et al. provide experimental evidence to this end. On the basis of their findings, they argue against the URM and in favor of a model of task‐dependent sentence comprehension. We show through simulations that the Swets et al. data do not constitute evidence for task‐dependent parsing because they can be explained by the URM. However, we provide decisive evidence from a German self‐paced reading study consistent with Swets et al.'s general claim about task‐dependent parsing. Specifically, we show that under certain conditions, ambiguous sentences can be read more slowly than their unambiguous counterparts, suggesting that the parser may create several parses, when required. Finally, we present the first quantitative model of task‐driven disambiguation that subsumes the URM, and we show that it can explain both Swets et al.'s results and our findings.     

Spontaneous Imitation of Fundamental Frequency and Speech Rate by Nonstutterers and Stutterers

Speech can be described either in terms of acoustics, as a perceptual outcome, or as a motor event. Central to theories of speech perception and production is an attempt to describe how these aspects of speech are interrelated. The present experiment investigated how the nonstutterers' and stutterers' reproductions of acoustically presented interrogative sentences were influenced by experimental variations of intonation (sentence initial vs. sentence final) and speech rate (normal vs. time compressed). We studied the effects of these stimulus manipulations on the speech rate and fundamental frequency (F₀ ) of 10 adult German-speaking nonstutterers and seven stutterers. Experimental manipulations of intonation and speech rate significantly influenced the syllable duration and speech rate of both normal speakers and stutterers. The fundamental frequency of the subjects' responses were also significantly influenced by the intonation of the stimulus. But the stutterers' increase in F₀ for stressed syllables was generally less pronounced than that of nonstutterers. These results imply that (a) the subjects not only extract linguistic meaning from intonation but that they also store extragrammatical speech rate information, and (b) the speakers adopt these speech rate variations for their own productions. Generally, these results demonstrate that speech perception is not limited to extracting linguistically invariant information. The results show that speakers actively generate their own prosody and that this generative process is influenced by the prosodic structure of another speaker's antecedent speech. The implications of these results for theories of speech production are discussed.     

Semantic binding,not attentional control,generates coherent global structure in children's narrative memory

Encoding and retrieving global narrative structure influences children's narrative recall. The influence of age and attentional/executive resources on binding processes during sentence list recall was examined in 5- to 6- and 8- to 9-year-old children. Older and younger children showed superior recall of lists, and achieved higher scores on two metrics of chunking; access to different sentences (i.e., number of chunks) and sentence completion (i.e., chunk size), when lists were presented within a coherent global structure. Children's list recall and sentence access, but not their sentence completion scores, were affected by a concurrent self-paced attention-demanding task. Children, unlike adults, engage in active storage of verbal information in thematically related sentence lists. The coherence-advantage effect was stable across age groups and insensitive to the secondary task. Overall, findings imply that semantic binding generates stronger memory representations and superior recall for sentences within a story context than for sentence sets that lack global narrative structure.     

The development of sentence interpretation: effects of perceptual, attentional and semantic interference

How does the development and consolidation of perceptual, attentional, and higher cognitive abilities interact with language acquisition and processing? We explored children's (ages 5–17) and adults’ (ages 18–51) comprehension of morphosyntactically varied sentences under several competing speech conditions that varied in the degree of attentional demands, auditory masking, and semantic interference. We also evaluated the relationship between subjects’ syntactic comprehension and their word reading efficiency and general ‘speed of processing’. We found that the interactions between perceptual and attentional processes and complex sentence interpretation changed considerably over the course of development. Perceptual masking of the speech signal had an early and lasting impact on comprehension, particularly for more complex sentence structures. In contrast, increased attentional demand in the absence of energetic auditory masking primarily affected younger children's comprehension of difficult sentence types. Finally, the predictability of syntactic comprehension abilities by external measures of development and expertise is contingent upon the perceptual, attentional, and semantic milieu in which language processing takes place.     

Brain activity varies with modulation of dynamic pitch variance in sentence melody

Fourteen native speakers of German heard normal sentences, sentences which were either lacking dynamic pitch variation (flattened speech), or comprised of intonation contour exclusively (degraded speech). Participants were to listen carefully to the sentences and to perform a rehearsal task. Passive listening to flattened speech compared to normal speech produced strong brain responses in right cortical areas, particularly in the posterior superior temporal gyrus (pSTG). Passive listening to degraded speech compared to either normal or flattened speech particularly involved fronto-opercular and subcortical (Putamen, Caudate Nucleus) regions bilaterally. Additionally the Rolandic operculum (premotor cortex) in the right hemisphere subserved processing of neat sentence intonation. As a function of explicit rehearsing sentence intonation we found several activation foci in the left inferior frontal gyrus (Broca's area), the left inferior precentral sulcus, and the left Rolandic fissure. The data allow several suggestions: First, both flattened and degraded speech evoked differential brain responses in the pSTG, particularly in the planum temporale (PT) bilaterally indicating that this region mediates integration of slowly and rapidly changing acoustic cues during comprehension of spoken language. Second, the bilateral circuit active whilst participants receive degraded speech reflects general effort allocation. Third, the differential finding for passive perception and explicit rehearsal of intonation contour suggests a right fronto-lateral network for processing and a left fronto-lateral network for producing prosodic information. Finally, it appears that brain areas which subserve speech (frontal operculum) and premotor functions (Rolandic operculum) coincidently support the processing of intonation contour in spoken sentence comprehension.     

NOTES ON CONTRIBUTORS

Naturalistic studies have reported contextual facilitation of oral reading in passage‐length materials, but inconsistent results have been obtained in studies of sentence‐long contexts. While studies of intrasentence contextual facilitation effects constitute conservative tests of top‐down reading theories, failure to observe such effects raises serious doubts concerning the scope of those theories. The present study examined both quantitative and qualitative aspects of children's oral reading of words in isolation and in sentence‐length contexts. Results indicated that, although sentence‐long context did not facilitate reading accuracy, children did appear to be exploiting contextual information in their reading of sentences, with a relatively high proportion of reading errors being contextually acceptable. Introspective data suggested that children may have adopted different reading strategies in the two context conditions, using a slower, bottom‐up strategy for words in isolation and a fluent, top‐down strategy for the sentences.     

Syntactic Creativity Errors in Children's Wh-Questions

Previous work has reported that children creatively make syntactic errors that are ungrammatical in their target language, but are grammatical in another language. One of the most well-known examples is medial wh-question errors in English-speaking children's wh-questions (e.g., What do you think who the cat chased? from Thornton, 1990). The evidence for this non-target-like structure in both production and comprehension has been taken to support the existence of innate, syntactic parameters that define all possible grammatical variation, which serve as a top-down constraint guiding children's language acquisition process. The present study reports new story-based production and comprehension experiments that challenge this interpretation. While we replicated previous observations of medial wh-question errors in children's sentence production (Experiment 1), we saw a reduction in evidence indicating that English-speaking children assign interpretations that conform to the medial wh-question pattern (Experiment 2). Crucially, we found no correlation between production and comprehension errors (Experiment 3). We suggest that these errors are the result of children's immature sentence production mechanisms rather than immature grammatical knowledge.     

Idiosyncratic effects of interviewer behavior on the accuracy of children's responses

Children are interviewed to provide information about past events in various contexts (e.g., police interviews, court proceedings, therapeutic interviews). During an interview, various factors may influence the accuracy of children's responses to questions about recent events. However, behavioral research in this area is limited. Sparling et al. (2011) showed that children frequently provided inaccurate responses to questions about video clips they just watched depending on the antecedents (i.e., the way a question was asked) and consequences (i.e., the response of the interviewer to their answers). In the current study, we replicated and extended the procedures reported by Sparling et al. and found that two of five children were sensitive to the various antecedents and consequences that we manipulated. Our findings indicate a need for more research in this area to determine the relevant environmental variables that affect children's response accuracy.     

Examining the role of lexical frequency in the acquisition and processing of sentential complements

We present empirical data showing that the relative frequency with which a verb normally appears in a syntactic construction predicts young children's ability to remember and repeat sentences instantiating that construction. Children aged 2;10–5;8 years were asked to repeat grammatical and ungrammatical sentential complement sentences (e.g., ‘I think + S’). The sentences contained complement-taking verbs (CTVs) used with differing frequencies in children's natural speech. All children repeated sentences containing high frequency CTVs (e.g., think) more accurately than those containing low frequency CTVs (e.g., hear), and made more sophisticated corrections to ungrammatical sentences containing high frequency CTVs. The data suggest that, like adults, children are sensitive to lexico-constructional collocations. The implications for language acquisition are discussed.     

Teachers' ratings of children's behaviour in relation to blood lead levels

Teachers rated the behaviour of 166 children whose blood lead levels had previously been determined. Ratings were made on the Conners Scale, the Rutter Scale B(2), and Needleman's Scale. The results broadly replicated the findings of Needleman et al. (1979) in so far as they indicate a relationship between difficulties in attention and increased blood lead levels over the normal range of blood lead values. ‘Hyperactivity’ on the Rutter and Conners scales were found to be significantly related to children's blood lead levels, independent of chronological age. Social factors remain uncontrolled in this pilot study.     

Children's identification of actors and patients in prototypical and nonprototypical sentence types

This research examined if children organize language categories around a prototype. Based on previous research with adults, the hypothesis held that the prototypical transitive sentence contains an animate actor and patient and a highly prototypical verb. The question of interest was if factors that contribute to adult judgments of sentence prototypicality (such as actor-patient animacy and verb prototypicality) affect young childrens' accuracy in correctly identifying sentence actors and patients. That is, are children more likely to make correct identifications in prototypical sentences? Sixty-four 2- and 4-year-old children were trained to to ntify sentence actors and patients in prototypical or nonprototypical sentences and then tested for generalization to sentences of other types. Two factors, verb prototypicality and animacy of sentence participants, combined to influence children's accuracy in actor/patient identification. Regardless of training condition, children produced more correct responses to sentences with animate actors than to sentences with inanimate actors. There was an interaction with verb prototypicality such that it was more typical for inanimate actors to act upon animate patients with what are otherwise low prototype verbs (e.g., low in action, low in intentionality). The results of the study are consistent with the view that similar cognitive mechanisms operate in language and in other nonlinguistic cognitive domains.     

The effect of grammatical complexity upon disfluency behavior of nonstuttering preschool children

The effect of grammatical complexity on the disfluency behavior of nonstuttering 3- and 4-yr-old children was examined. Thirty normal children repeated after the examiner 30 sentences which represented six different grammatical constructions. These grammatical constructions represented a range of grammatical complexity.The total number of disfluencies that occurred in each sentence type was compared. The occurrence of specific disfluency categories in each sentence type was also examined. Subjects produced significantly more disfluencies on passive sentences than on any other sentence type. The passive elicited significantly more interjections, word repetitions, and revisions than the other sentence types.The effect of sentence type on imitation performance was also examined. The auxiliary Have and negative sentence types elicited significantly more imitation errors than other sentence types. Initiation and fluency performance for individual subjects were also examined.The results of the present investigation suggest that when grammatical complexity is controlled, the relationship between disfluencies and grammatical complexity is complicated. When grammatical constructions were relatively difficult for children, complexity affected the occurrence of disfluencies. However, factors other than grammatical complexity affect the occurrence of disfluencies in pre-school children.     

Building syntactic structures in speaking: a bilingual exploration

In a series of three experiments we investigated syntactic priming using a sentence recall task. Participants read and memorized a target sentence for later recall. After reading a prime sentence and engaging in a distraction task, they were asked to produce the target sentence aloud. Earlier investigations have shown that this task is sensitive to a syntactic priming effect. That is, the syntactic form of the prime sentence sometimes influences the syntactic form of the recalled target. In this paper we report on a variation on this task, using Spanish-English bilingual participants. In the first two experiments we replicated the prepositional phrase priming effect using English target sentences and Spanish prime sentences. In the final experiment we investigated two additional syntactic forms, using Spanish target sentences and English prime sentences. Implications for models of syntax generation and bilingual speech production are discussed.     

Characterizing sentence intonation in a right hemisphere-damaged population

Current production studies present a mixed view of right hemisphere-damaged (RHD) patients' ability to produce normal sentence intonation. The present study characterized the sentence intonation of RHD patients, focusing on a greater number of acoustic parameters than past works, and relying on more naturally elicited speech samples through use of a story completion task. Eight RHD speakers and seven nonneurological control subjects produced declarative and imperative sentences as well as yes-no and wh-questions. Slope of F0 change, linearity of pitch contour, and variance of F0 points were calculated for each utterance as a whole, as well as for the preterminal and the terminal contour separately. RHD contours were less linear and flatter in F0 decline than normal controls for the declarative sentences. The patients' yes-no questions also differed from normal productions, displaying smaller F0 dispersion around a mean F0. Preterminal range values were more restricted for patients' utterances of yes-no questions, while terminal properties between groups differed for three of the four sentence types examined. The present results suggest some disturbance in the patients' ability to manipulate fundamental frequency across sentential domains. These data are discussed in terms of current theories of a general dysprosody in RHD patients.     

Modeling the Influence of Language Input Statistics on Children's Speech Production

We trained a computational model (the Chunk-Based Learner; CBL) on a longitudinal corpus of child–caregiver interactions in English to test whether one proposed statistical learning mechanism—backward transitional probability—is able to predict children's speech productions with stable accuracy throughout the first few years of development. We predicted that the model less accurately reconstructs children's speech productions as they grow older because children gradually begin to generate speech using abstracted forms rather than specific “chunks” from their speech environment. To test this idea, we trained the model on both recently encountered and cumulative speech input from a longitudinal child language corpus. We then assessed whether the model could accurately reconstruct children's speech. Controlling for utterance length and the presence of duplicate chunks, we found no evidence that the CBL becomes less accurate in its ability to reconstruct children's speech with age.     

绕口令效应对汉语阅读影响的眼动研究

绕口令效应指无论朗读还是默读,绕口令的阅读时间都长于正常句子的阅读时间。本研究采用Eyelink 2000型眼动仪,通过两个实验考察汉语阅读中的绕口令效应及其对知觉广度的影响。实验1结果表明:与阅读非绕口令相比,绕口令的阅读时间和注视次数均显著增加而阅读速度和平均眼跳幅度均显著下降。实验2结果表明:绕口令的知觉广度为注视点右侧1~2个汉字,控制句的知觉广度为注视点右侧2~3个汉字。结果说明汉语中存在绕口令效应,使读者知觉广度变小,阅读效率下降。。     

Young children's comprehension of number markers

Young children's comprehension of four number markers (demonstratives, regular nouns, third person of the auxiliary be, and regular present tense verbs) was investigated through their presentation in sentences conveying non-redundant information about number. Comprehension of each sentence was tested in two tasks: pointing to one of a pair of line drawings and acting out with toys the action described by a sentence. The results indicated that, firstly, the number information carried by the verb is rarely attended to or mastered before some component of the noun phrase; and, secondly, that the is/are allomorphs of the auxiliary be are mastered much earlier than the singular and plural forms of third-person regular present tense verbs. Both the overall order of difficulty in understanding the four number markers investigated and the analysis of individual data were consistent with the developmental sequence reported by several authors for the acquisition of grammatical morphemes in spontaneous speech production.     

单字词和复合词预视加工的差异性研究：词边界信息无影响

本实验采用眼动轨迹记录法并结合边界范式（Rayner, 1975），操纵单字词和双字复合词的首字为一致预视或假字预视，考察单字词和复合词预视加工的差异性。另外，通过在中文句子中加入词边界信息——词间阴影，以考察词间阴影对单字词和复合词预视加工的影响。实验结果表明，复合词的预视效应大于单字词，并且词间阴影对单字词和复合词的预视加工均没有显著影响。因此，与印欧语系相比，中文阅读中更大更强的预视效应需从更深层次的语言和认知因素进行探讨。该结果更倾向于支持词切分和词汇识别模型。     

Young children use their hands to tell their mothers what to say

Children produce their first gestures before their first words, and their first gesture+word sentences before their first word+word sentences. These gestural accomplishments have been found not only to predate linguistic milestones, but also to predict them. Findings of this sort suggest that gesture itself might be playing a role in the language‐learning process. But what role does it play? Children's gestures could elicit from their mothers the kinds of words and sentences that the children need to hear in order to take their next linguistic step. We examined maternal responses to the gestures and speech that 10 children produced during the one‐word period. We found that all 10 mothers ‘translated’ their children's gestures into words, providing timely models for how one‐ and two‐word ideas can be expressed in English. Gesture thus offers a mechanism by which children can point out their thoughts to mothers, who then calibrate their speech to those thoughts, and potentially facilitate language‐learning.