The rational inference, or noisy channel, account of language comprehension predicts that comprehenders are sensitive to the probabilities of different interpretations for a given sentence and adapt as these probabilities change (Gibson, Bergen & Piantadosi, 2013). This account provides an important new perspective on aphasic sentence comprehension: aphasia may increase the likelihood of sentence distortion, leading people with aphasia (PWA) to rely more on the prior probability of an interpretation and less on the form or structure of the sentence (Gibson, Sandberg, Fedorenko, Bergen & Kiran, 2015). We report the results of a sentence-picture matching experiment that tested the predictions of the rational inference account and other current models of aphasic sentence comprehension across a variety of sentence structures. Consistent with the rational inference account, PWA showed similar sensitivity to the probability of particular kinds of form distortions as age-matched controls, yet overall their interpretations relied more on prior probability and less on sentence form. As predicted by rational inference, but not by other models of sentence comprehension in aphasia, PWA’s interpretations were more faithful to the form for active and passive sentences than for direct object and prepositional object sentences. However contra rational inference, there was no evidence that individual PWA’s severity of syntactic or semantic impairment predicted their sensitivity to form versus the prior probability of a sentence, as cued by semantics. These findings confirm and extend previous findings that suggest the rational inference account holds promise for explaining aphasic and neurotypical comprehension, but they also raise new challenges for the account.

In this study we examined the interactions of context availability, polysemy, word frequency, and orthographic neighborhood variables during lexical processing. Context availability and polysemy interacted, in that words that were both lower in context availability and had fewer related senses were especially disadvantaged, as was originally reported by Tokowicz and Kroll (2007). Word frequency interacted with both polysemy and context availability, in that the effects of polysemy and context availability were stronger for lower-frequency words. Finally, orthographic neighborhood size and frequency both interacted with polysemy: the effect of polysemy was greater for words with smaller orthographic neighborhoods and a greater number of higherfrequency neighbors. These findings provide support for the context availability hypothesis (Schwanenflugel & Shoben, 1983). Specifically, the feedback activation account (Hino & Lupker, 1996) offers a mechanistic explanation of our findings that is rooted in feedback from semantic to orthographic representations.

The human auditory system can quickly accommodate foreign-accented speech. However, the cognitive mechanisms underlying perceptual adjustment to non-native speech are not fully understood. The current study examined the perceptual consequences of adaptation toward foreign-accented speech on native language perception. Native English speakers performed an auditory shadowing task on word-length utterances in English. There were four blocks of trials. The words in the critical block (Block 3) were spoken by either a native American English speaker or a native Spanish speaker. The speaker in flanking blocks (Blocks 1–2, 4) was the same speaker, a different speaker with the same accent, or a different speaker with a different accent. Shadowing response times in the critical block were used to assess rapid perceptual adjustment and readjustment. Results showed that the nature of the preceding context influenced response times. Response times for items in the first quartile of the critical block were reliably slower when accent and talker changed than when accent and talker remained constant. These findings suggest that listeners develop perceptual expectations about ongoing speech, which when violated incur a short-term processing cost even for spoken words in the listeners’ native language.

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