Effects of individual differences in text exposure on sentence comprehension.

Linguistic experience plays a clear role in accounting for variability in sentence comprehension behavior across individuals and across sentence types. We aimed to understand how individual differences in reading experience predict reading behavior. Corpus analyses revealed the frequencies with which our experimental items appeared in written and spoken language. We hypothesized that reading experience should affect sentence comprehension most substantially for sentence types that individuals primarily encounter through written language. Readers with more text exposure were faster and more accurate readers overall, but they read sentence types biased to written language particularly faster than did readers with less text exposure. We see clear effects of text exposure on sentence comprehension in ways that allow explicit links between written and spoken corpus statistics and behavior. We discuss theoretical implications of effects of text exposure for experience-based approaches to sentence processing.

Parafoveal processing of inflectional morphology in Russian: A within-word boundary-change paradigm.

The present study examined whether the inflectional morphology on Russian nouns is processed parafoveally in words longer than five characters while the eyes are fixated on the word. A modified boundary-change paradigm was used to examine parafoveal processing of nominal case markings within a currently fixated word n. The results elicited identical preview benefit for both first and second-pass measures on the post boundary and whole word regions. The morphologically related preview benefit (vs. nonword) was observed for first and second-pass measures as early as pre-boundary, post-boundary, and whole word regions. Additionally the morphologically related preview elicited cost (vs. identical) for first-pass measures on the post-boundary region, total time for the whole word, and regressions into the pre-boundary region. The contribution of the study is two-fold. First, this is the first study to use within-word boundary changes to study the parafoveal processing of inflectional morphology in Russian. Second, we provide additional evidence that inflectional morphology can be integrated parafoveally while reading a language with linear concatenative morphology.

Developmental trajectory of mismatch negativity and visual event-related potentials in healthy controls: Implications for neurodevelopmental vs. neurodegenerative models of schizophrenia.

Sensory processing deficits are core features of schizophrenia, reflected in impaired generation of event-related potential (ERP) measures such as auditory mismatch negativity (MMN) and visual P1. To understand the potential time course of development of deficits in schizophrenia, we obtained MMN to unattended duration, intensity and frequency deviants, and visual P1 to attended LSF stimuli, in 43 healthy individuals ages 6 to 25years (mean 17), and compared results to data from 30 adult schizophrenia patients (mean age 38). We analyzed "time-domain" measures of amplitude and latency, and event-related spectral perturbation (ERSP, "time-frequency") to evaluate underlying neurophysiological mechanisms. Duration and intensity MMN amplitudes increased from childhood to late adolescence, while frequency MMN reached maximum amplitude during early development. As reported previously, in ERSP analyses, MMN activity corresponded primarily to theta-band (4-7Hz) activity, while responses to standards occurred primarily in alpha (8-12Hz) across age groups. Both deviant-induced theta and standard-induced alpha activity declined significantly with age for all deviant types. Likewise, visual P1 also showed an amplitude decline over development, reflecting a reduction in both evoked power and ITC. While MMN "difference" waveform ERP data suggest failure of maturation in schizophrenia, MMN ERSP analyses instead support a neurodegenerative process, as these isolate responses to deviants and standards, showing large low-frequency evoked power for both in children. Neurodegenerative processes are also supported by large visual P1 amplitudes and large low-frequency evoked power in children, in contrast with adult schizophrenia. Sensory processing deficits in schizophrenia may be related to accelerated synaptic pruning.