Auditory perception in the ageing brain:the role of inhibition and facilitation in early processing

AbstractAging affects the interplay between peripheral and cortical auditory processing. Previous studies have demonstrated that older adults are less able to regulate afferent sensory information and are more sensitive to distracting information. Using auditory event-related potentials we investigated the role of cortical inhibition on auditory and audiovisual processing in younger and older adults. Across puretone, auditory and audiovisual speech paradigms older adults showed a consistent pattern of inhibitory deficits, manifested as increased P50 and/or N1 amplitudes and an absent or significantly reduced N2. Older adults were still able to use congruent visual articulatory information to aid auditory processing but appeared to require greater neural effort to resolve conflicts generated by incongruent visual information. In combination, the results provide support for the Inhibitory Deficit Hypothesis of aging. They extend previous findings into the audiovisual domain and highlight older adults' ability to benefit from congruent visual information during speech processing

The Acquisition and Processing of Backwards Anaphora

This dissertation investigates long-distance backwards pronominal dependencies (backwards anaphora or cataphora) and constraints on such dependencies from the viewpoint of language development and real-time language processing. Based on the findings from a comprehension experiment with Russian-speaking children and on real-time sentence processing data from English and Russian adults I argue for a position that distinguishes structural and non-structural constraints on backwards anaphora. I show that unlike their non-syntactic counterparts, structural constraints on coreference, in particular Principle C of the Binding Theory (Chomsky 1981), are active at the earliest stage of language development and of real-time processing. In language acquisition, the results of a truth-value judgment task with 3-6 year old Russian-speaking children reveal a striking developmental asymmetry between Principle C, a cross-linguistically consistent syntactic constraint on coreference, and a Russian-specific discourse constraint on coreference. Whereas Principle C is respected by children already at the age of three, the Russian-specific (discourse) constraint is not operative in child language until the age of five. These findings present a challenge for input-driven accounts of language acquisition and are most naturally explained in theories that admit the existence of innately specified principles that underlie linguistic representations. In real-time processing, the findings from a series of self-paced reading experiments on English and Russian show that in backwards anaphora contexts the parser initiates an active search for an antecedent for the pronoun which is limited to positions that are not subject to structural constraints on coreference, e.g. Principle C. This grammatically constrained active search mechanism associated observed in the processing of backwards anaphora is similar to the mechanism found in the processing of another type of a long-distance dependency, the wh-dependency. I suggest that the early application of structural constraints on long-distance dependencies is due to reasons of parsing efficiency rather than due to their architectural priority, as such constraints aid to restrict the search space of possible representations to be built by the parser. A computational parsing algorithm is developed that combines the constrained active search mechanism with a strict incremental left-to-right structure building procedure

Predicting complex syntactic structure in real time:Processing of negative sentences in Russian

In Russian negative sentences the verb's direct object may appear either in the accusative case, which is licensed by the verb (as is common cross-linguistically), or in the genitive case, which is licensed by the negation (Russian-specific “genitive-of-negation” phenomenon). Such sentences were used to investigate whether case marking is employed for anticipating syntactic structure, and whether lexical heads other than the verb can be predicted on the basis of a case-marked noun phrase. Experiment 1, a completion task, confirmed that genitive-of-negation is part of Russian speakers’ active grammatical repertoire. In Experiments 2 and 3, the genitive/accusative case manipulation on the preverbal object led to shorter reading times at the negation and verb in the genitive versus accusative condition. Furthermore, Experiment 3 manipulated linear order of the direct object and the negated verb in order to distinguish whether the abovementioned facilitatory effect was predictive or integrative in nature, and concluded that the parser actively predicts a verb and (otherwise optional) negation on the basis of a preceding genitive-marked object. Similarly to a head-final language, case-marking information on preverbal noun phrases (NPs) is used by the parser to enable incremental structure building in a free-word-order language such as Russian. </jats:p

A 'no' with a trace of 'yes':a mouse-tracking study of negative sentence processing

There is strong evidence that comprehenders can parse sentences in an incremental fashion. However, when the sentence contains a negation, the evidence is less clear. Previous work has shown that increasing the pragmatic felicity of a negative sentence reduces or eliminates any processing overhead relative to affirmative sentences. However, in previous work felicity has gone hand-in-hand with the predictability of critical material in a sentence. In three experiments reported here, we presented equally felicitous sentences with critical material of varying predictability (operationalised as the number of possible completions) to test whether this might be a critical factor determining the ease with which partial sentences containing a negation are interpreted. Participants completed a truth-value judgement task (Experiment 1) or a sentence completion task (Experiments 2 and 3) after viewing a visual environment that provided the context for a test sentence, which could differ in truth value (in Experiment 1 only), polarity (affirmative or negative), and number of possible completions (one, two, or three). In all three experiments, we recorded response times and accuracy, but also response dynamics via participants’ computer mouse trajectories, allowing us to test specific hypotheses about the time course of comprehension. Across all experiments, in conditions with one or two possible targets, we observed consistent detrimental effects of negative polarity, suggesting that the difficulty in processing negation cannot be reduced to effects relating to predictability or pragmatic felicity. We discuss this finding in relation to incremental and two-stage models of processing and outline a new account of the processing difficulty arising from negation in terms of a conflict between what is locally activated on the basis of individual words and phrases and the global meaning of a negative sentence

Differential effects of constraints in the processing of Russian cataphora.

Anaphoric relations between pronouns and their antecedents are subject to a number of different linguistic constraints, which exclude the possibility of coreference in specific syntactic or discourse contexts. Constraints on anaphora may, in principle, impact online sentence processing in a couple of different ways. They may act as constraints on the generation of interpretations, preventing illicit anaphoric relations from ever being considered. Alternatively, they may act as later filters on interpretations, rejecting candidate interpretations after initial consideration. A number of previous studies have sought to determine which of these mechanisms accurately describes the online impact of constraints on anaphora. The current studies present evidence that there is no uniform answer to this question, and that the two mechanisms are both used, for different constraints. Evidence for this is drawn from studies on the processing of two constraints on backwards anaphora or cataphora in Russian that apply in superficially similar contexts but that differ in a number of respects. One self-paced reading study and two judgement studies are reported. The self-paced reading study manipulates the gender congruency between a pronoun and a following name in three pairs of conditions. In conditions where the pronoun -name configuration violates no constraints on anaphora a gender mismatch effect was observed following the name, as in previous studies, suggesting that comprehenders actively search for an antecedent following a cataphoric pronoun. In conditions where the pronoun -name configuration violates Principle C of the classical binding theory no effect of the gender manipulation was observed, suggesting that comprehenders do not even consider the possibility of interpretations that violate this constraint. In conditions where the pronoun-name configuration violates a Russian-specific constraint on cataphora a gender match effect was observed following the name, the reverse of the finding in the no-constraint conditions, suggesting that the constraint applies as a filter on candidate interpretations