Tracking the continuity of language comprehension: computer mouse trajectories suggest parallel syntactic processing

Although several theories of online syntactic processing assume the parallel activation of multiple syntactic representations, evidence supporting simultaneous activation has been inconclusive. Here, the continuous and non-ballistic properties of computer mouse movements are exploited, by recording their streaming x, y coordinates to procure evidence regarding parallel versus serial processing. Participants heard structurally ambiguous sentences while viewing scenes with properties either supporting or not supporting the difficult modifier interpretation. The curvatures of the elicited trajectories revealed both an effect of visual context and graded competition between simultaneously active syntactic representations. The results are discussed in the context of 3 major groups of theories within the domain of sentence processing.     

Eye movements and spoken language comprehension: effects of visual context on syntactic ambiguity resolution

When participants follow spoken instructions to pick up and move objects in a visual workspace, their eye movements to the objects are closely time-locked to referential expressions in the instructions. Two experiments used this methodology to investigate the processing of the temporary ambiguities that arise because spoken language unfolds over time. Experiment 1 examined the processing of sentences with a temporarily ambiguous prepositional phrase (e.g., "Put the apple on the towel in the box") using visual contexts that supported either the normally preferred initial interpretation (the apple should be put on the towel) or the less-preferred interpretation (the apple is already on the towel and should be put in the box). Eye movement patterns clearly established that the initial interpretation of the ambiguous phrase was the one consistent with the context. Experiment 2 replicated these results using prerecorded digitized speech to eliminate any possibility of prosodic differences across conditions or experimenter demand. Overall, the findings are consistent with a broad theoretical framework in which real-time language comprehension immediately takes into account a rich array of relevant nonlinguistic context.     

On the parity of structural persistence in language production and comprehension

Structural priming creates structural persistence. That is, differences in experience with syntax can change subsequent language performance, and the changes can be observed in both language production and comprehension. However, the effects in comprehension and production appear to differ. In comprehension, persistence is typically found when the verbs are the same in primes and targets; in production, persistence occurs without verb overlap. The contrast suggests a theoretically important hypothesis: parsing in comprehension is lexically driven while formulation in production is structurally driven. A major weakness in this hypothesis about comprehension-production differences is that its empirical motivation rests on the outcomes of experiments in which the priming manipulations differ, the primed sentence structures differ, and the measures of priming differ. To sharpen the comparison, we examined structural persistence with and without verb overlap in both reading comprehension and spoken production, using the same prime presentation procedure, the same syntactic structures, the same sentences, and the same participants. These methods yielded abstract structural persistence in comprehension as well as production. A measure of the strength of persistence revealed significant effects of priming and verb overlap without significant comprehension—production differences. This argues for uniformity in the structural mechanisms of language processing.     

The neural basis of syntactic deficits in primary progressive aphasia

Patients with primary progressive aphasia (PPA) vary considerably in terms of which brain regions are impacted, as well as in the extent to which syntactic processing is impaired. Here we review the literature on the neural basis of syntactic deficits in PPA. Structural and functional imaging studies have most consistently associated syntactic deficits with damage to left inferior frontal cortex. Posterior perisylvian regions have been implicated in some studies. Damage to the superior longitudinal fasciculus, including its arcuate component, has been linked with syntactic deficits, even after gray matter atrophy is taken into account. These findings suggest that syntactic processing depends on left frontal and posterior perisylvian regions, as well as intact connectivity between them. In contrast, anterior temporal regions, and the ventral tracts that link frontal and temporal language regions, appear to be less important for syntax, since they are damaged in many PPA patients with spared syntactic processing.     

The development of Japanese passive syntax as indexed by structural priming in comprehension

A number of previous studies reported a phenomenon of syntactic priming with young children as evidence for cognitive representations required for processing syntactic structures. However, it remains unclear how syntactic priming reflects children's grammatical competence. The current study investigated structural priming of the Japanese passive structure with 5- and 6-year-old children in a visual-world setting. Our results showed a priming effect as anticipatory eye movements to an upcoming referent in these children but the effect was significantly stronger in magnitude in 6-year-olds than in 5-year-olds. Consistently, the responses to comprehension questions revealed that 6-year-olds produced a greater number of correct answers and more answers using the passive structure than 5-year-olds. We also tested adult participants who showed even stronger priming than the children. The results together revealed that language users with the greater linguistic competence with the passives exhibited stronger priming, demonstrating a tight relationship between the effect of priming and the development of grammatical competence. Furthermore, we found that the magnitude of the priming effect decreased over time. We interpret these results in the light of an error-based learning account. Our results also provided evidence for prehead as well as head-independent priming.     

The effect of syntactic encoding on sentence comprehension in aphasia.

This study compared two levels of syntactic encoding with respect to their effect on aphasics' auditory comprehension. The same informational content was presented either as an embedded sentence or as two contiguous simplé propositions. A similar contrast was utilized to compare sentences containing relational terms of time, comparison, instrumentality, as well as sentences involving conjunction reduction, with parallel messages expressed in expanded, simplified form. A picture-verification paradigm was used. Comprehension was significantly enhanced only in the case of embedded sentences, with a tendency for Broca's aphasics to show the maximum effects.     

On the categorization of aphasic typologies: the SOAP (a test of syntactic complexity)

This paper presents a new measure of syntactic comprehension abilities in brain-damaged populations known as the SOAP (Subject-relative, Object-relative, Active, and Passive), along with data supporting its sensitivity and specificity. This assessment tool examines comprehension of sentences (matched for length) of four syntactic construction types: active, passive, subject-relative, and object-relative. Data are presented that indicate that the SOAP provides a sensitive and reliable differentiation of aphasia subgroups. The SOAP's sensitivity in differentiating broad behavioral (anterior/posterior-lesioned) groups is compared to the auditory comprehension component of the Boston Diagnostic Aphasia Examination (BDAE), supporting its sensitivity differentiating between anterior- and posterior-lesioned groups. It is argued that this tool can be an important accompaniment to standard aphasia assessment batteries in more sensitively defining syntactic comprehension deficits.     

The relation between children's reading comprehension level and their comprehension of idioms

We report an investigation of 9-year-olds' ability to interpret idioms in relation to their reading comprehension level. We manipulated whether the idioms were transparent or opaque, whether they were real or novel, whether they were presented in isolation or in a supportive narrative context. As predicted, children were better able to explain the meanings of idioms in context than in isolation. The good and poor comprehenders did not differ in their abilities to interpret transparent idioms in context, but the poor comprehenders were significantly worse at using context to work out the meanings of opaque idioms. The explanation task revealed the source of information used by the children to derive nontarget interpretations. We discuss these findings in relation to idiom processing strategies and Levorato and Cacciari's global elaboration model.     

Semantic operations in aphasic comprehension: implications for the cortical organization of language.

We provide data on the neurological basis of two semantic operations at the sentence level: aspectual coercion and complement coercion. These operations are characterized by being purely semantic in nature; that is, they lack morphosyntactic reflections. Yet, the operations are mandatory (i.e., they are indispensable for the semantic well formedness of a sentence). Results indicate that, whereas Broca's patients have little or no trouble understanding sentences requiring these operations (performance was above chance for all conditions), Wernicke's patients performed at normal-like levels only for sentences that did not require these operations. These findings suggest that sentence-level semantic operations rely very specifically on the integrity of the cortical area associated with Wernicke's aphasia, but not on the region corresponding to Broca's aphasia. In the context of other findings from lesion and imaging studies, this evidence allows a view of the cortical distribution of language capacity that is drawn along a linguistic line, one which distinguishes syntactic from semantic operations.     

The nature of the phonological disorder in conduction aphasia

Sequences of attempts to name pictured objects were used to examine phonological dysfunction in three diagnostic subgroups of aphasia. A prevalence of "phonologically-oriented sequences" (i.e., those sequences that contained only attempts with a phonological resemblance to the target word) was found to be a diagnostic criterion for conduction aphasia. When compared to a group of Broca's (n = 7) and Wernicke's (n = 5) aphasics, all the conduction aphasics (n = 6) produced proportionately more of such phonologically-oriented sequences on a picture naming test. An examination of the phonologically-oriented sequences produced by the conduction aphasics indicates that speech production in conduction aphasia involves dysfunction at an early stage of sound-encoding. The theoretical implications of this view are discussed.     

Theories of spoken word recognition deficits in aphasia: evidence from eye-tracking and computational modeling

We used eye-tracking to investigate lexical processing in aphasic participants by examining the fixation time course for rhyme (e.g., carrot-parrot) and cohort (e.g., beaker-beetle) competitors. Broca’s aphasic participants exhibited larger rhyme competition effects than age-matched controls. A re-analysis of previously reported data (Yee, Blumstein, & Sedivy, 2008) confirmed that Wernicke’s aphasic participants exhibited larger cohort competition effects. Individual-level analyses revealed a negative correlation between rhyme and cohort competition effect size across both groups of aphasic participants. Computational model simulations were performed to examine which of several accounts of lexical processing deficits in aphasia might account for the observed effects. Simulation results revealed that slower deactivation of lexical competitors could account for increased cohort competition in Wernicke’s aphasic participants; auditory perceptual impairment could account for increased rhyme competition in Broca’s aphasic participants; and a perturbation of a parameter controlling selection among competing alternatives could account for both patterns, as well as the correlation between the effects. In light of these simulation results, we discuss theoretical accounts that have the potential to explain the dynamics of spoken word recognition in aphasia and the possible roles of anterior and posterior brain regions in lexical processing and cognitive control.     

Metacognition in Taiwan: students' calibration of comprehension and performance

Researchers have increasingly investigated the role played by metacognition in students' learning and performance. Metacognition is comprised of metacognitive knowledge and metacognitive experiences, and both components of metacognition are viewed as being important to learning and performance in academic settings. Metacognitive experiences involve, in part, students' awareness of progress on cognitive tasks. Such awareness is critical to learning, for students may fail to spend additional time reviewing or studying material if they believe they have understood the material adequately. In the present study we examined Taiwanese students' ability to assess their comprehension of passages following reading as well as their ability to predict the number of questions they would be able to answer about passage content. Following an actual test on the material, students were asked to assess how many questions they felt they answered correctly about a passage (postdiction). Students were able to predict comprehension and test performance at better than chance levels and were more accurate at postdiction than prediction. Students with better performance, as measured by comprehension test scores, were better at both prediction and postdiction of comprehension performance. However, students' self-assessments of general calibration ability did not relate to their test performance. The metacomprehension skills of Taiwanese students were quite similar to those previously found for western students, but also diverged in some respects.     

Love and the need for comprehension

The question of how well we need to be known, to be loved, is considered. A ‘second-person’ model is argued for, on which love requires that the beloved's demands to be known be respected. This puts pressure on the idea that lovers need to make a beloved's interests their own, taking that to require comprehension of the beloved's interests: a lover would have to appreciate the normative intelligibility and motivating force of an interest. The possibility of love with failure of comprehension is defended, using illustrations from Marilynne Robinson's novel Gilead.     

Test anxiety and comprehension efficiency: The role of prior knowledge and working memory deficits

The hypotheses that test anxiety is associated with a deficit in prior knowledge and/or working memory capacity, that anxiety impairs comprehension efficiency, and that deficits in knowledge and capacity underlie the efficiency impairment, were tested. In Study 1, high-anxiety students were characterized by lower scores in several vocabulary measures, compared with low-anxiety students. In Study 2, high-anxiety individuals showed inferior working memory capacity to low-anxiety individuals under evaluative stress conditions, but not under non-stress conditions. In Study 3 high-anxiety subjects exhibited lower efficiency scores than low-anxiety subjects in expository texts without a summary: The former employed a greater amount of reading time than the latter to acquire an equivalent amount of information. In addition, the disadvantage in efficiency associated with anxiety was removed when differences in vocabulary knowledge were partialled out statistically. Instead, that disadvantage was only reduced, but not eliminated, when differences in transitory working memory capacity were partialled out. Therefore, the prior knowledge deficit hypothesis accounts for the impairment in reading efficiency associated with high anxiety better than the transitory working memory reduction hypothesis.     

Neural network processing of natural language: II. Towards a unified model of corticostriatal function in learning sentence comprehension and non-linguistic sequencing

A central issue in cognitive neuroscience today concerns how distributed neural networks in the brain that are used in language learning and processing can be involved in non-linguistic cognitive sequence learning. This issue is informed by a wealth of functional neurophysiology studies of sentence comprehension, along with a number of recent studies that examined the brain processes involved in learning non-linguistic sequences, or artificial grammar learning (AGL). The current research attempts to reconcile these data with several current neurophysiologically based models of sentence processing, through the specification of a neural network model whose architecture is constrained by the known cortico-striato-thalamo-cortical (CSTC) neuroanatomy of the human language system. The challenge is to develop simulation models that take into account constraints both from neuranatomical connectivity, and from functional imaging data, and that can actually learn and perform the same kind of language and artificial syntax tasks. In our proposed model, structural cues encoded in a recurrent cortical network in BA47 activate a CSTC circuit to modulate the flow of lexical semantic information from BA45 to an integrated representation of meaning at the sentence level in BA44/6. During language acquisition, corticostriatal plasticity is employed to allow closed class structure to drive thematic role assignment. From the AGL perspective, repetitive internal structure in the AGL strings is encoded in BA47, and activates the CSTC circuit to predict the next element in the sequence. Simulation results from Caplan's [Caplan, D., Baker, C., & Dehaut, F. (1985). Syntactic determinants of sentence comprehension in aphasia. Cognition, 21, 117-175] test of syntactic comprehension, and from Gomez and Schvaneveldts' [Gomez, R. L., & Schvaneveldt, R. W. (1994). What is learned from artificial grammars?. Transfer tests of simple association. Journal of Experimental Psychology: Learning, Memory and Cognition, 20, 396-410] artificial grammar learning experiments are presented. These results are discussed in the context of a brain architecture for learning grammatical structure for multiple natural languages, and non-linguistic sequences.     

Selective preservation of a lexical category in aphasia: Dissociations in comprehension of body parts and geographical place names following focal brain lesion

Abstract

The selective dissociation of memory for proper names is discussed in the context of a review of dissociations involving broadly defined vs narrowly defined semantic categories in brain damaged adults. Two narrowly defined categories for which dissociations have been reported are body parts (selectively impaired in comprehension) and geographical place names (selectively preserved in comprehension). In this study, 167 aphasic patients were tested for their ability to correctly identify body parts and map locations from spoken names, relative to a baseline for correct responses on general word discrimination (object identification). Wernicke's aphasics and Global aphasics both had significantly more success in pointing to named map locations and significantly worse performance in pointing to named body parts than they had in selecting other objects from multiple choice. Anomic aphasics showed precisely the opposite pattern of results. Other aphasic subgroups (Broca's aphasics. Mixed Nonfluent aphasics. Conduction aphasics, Transcortical Motor and Transcortical Sensory aphasics, and Mixed Fluent aphasics) did not show significant deviations in either direction. We suggest that the selective preservation for place names may be related to their status as proper names.     

Reading span task performance,linguistic experience,and the processing of unexpected syntactic events

Accounts of individual differences in online language processing ability often focus on the explanatory utility of verbal working memory, as measured by reading span tasks. Although variability in reading span task performance likely reflects individual differences in multiple underlying traits, skills, and processes, accumulating evidence suggests that reading span scores also reflect variability in the linguistic experiences of an individual. Here, through an individual differences approach, we first demonstrate that reading span scores correlate significantly with measures of the amount of experience an individual has had with written language (gauged by measures that provide “proxy estimates” of print exposure). We then explore the relationship between reading span scores and online language processing ability. Individuals with higher reading spans demonstrated greater sensitivity to violations of statistical regularities found in natural language—as evinced by higher reading times (RTs) on the disambiguating region of garden-path sentences—relative to their lower span counterparts. This result held after statistically controlling for individual differences in a non-linguistic operation span task. Taken together, these results suggest that accounts of individual differences in sentence processing can benefit from a stronger focus on experiential factors, especially when considered in relation to variability in perceptual and learning abilities that influence the amount of benefit gleaned from such experience.     

Patterns of comprehension performance in agrammatic Broca's aphasia: a test of the Trace Deletion Hypothesis

We tested the core prediction of the Trace Deletion Hypothesis (TDH) of agrammatic Broca's aphasia, which contends that such patients' comprehension performance is normal for active reversible sentences but at chance level for passive reversible sentences. We analyzed the comprehension performance of 38 Italian Broca's aphasics with verified damage to Broca's area, who completed sentence-to-picture matching tasks using active and passive reversible sentences as stimuli. The results failed to confirm the predictions made by TDH: only a small minority (15%) performed at chance on passive sentences and better than chance on active sentences. Furthermore, the distribution of the 38 subjects' performance on passive sentences differed from that predicted by the TDH since many more subjects performed at better-than-chance levels than expected. We discuss the implication of these results for claims about the distribution of language processing mechanisms in the brain.     

Consequences of the serial nature of linguistic input for sentenial complexity

All other things being equal the parser favors attaching an ambiguous modifier to the most recent possible site. A plausible explanation is that locality preferences such as this arise in the service of minimizing memory costs—more distant sentential material is more difficult to reactivate than more recent material. Note that processing any sentence requires linking each new lexical item with material in the current parse. This often involves the construction of long-distance dependencies. Under a resource-limited view of language processing, lengthy integrations should induce difficulty even in unambiguous sentences. To date there has been little direct quantitative evidence in support of this perspective. This article presents 2 self-paced reading studies, which explore the hypothesis that dependency distance is a fundamental determinant of reading complexity in unambiguous constructions in English. The evidence suggests that the difficulty associated with integrating a new input item is heavily determined by the amount of lexical material intervening between the input item and the site of its target dependents. The patterns observed here are not straightforwardly accounted for within purely experience-based models of complexity. Instead, this work supports the role of a memory bottleneck in language comprehension. This constraint arises because hierarchical linguistic relations must be recovered from a linear input stream.