What's new? A comprehension bias in favor of informativity.

Language is used as a channel by which speakers convey, among other things, newsworthy and informative messages, i.e., content that is otherwise unpredictable to the comprehender. We therefore might expect comprehenders to show a preference for such messages. However, comprehension studies tend to emphasize the opposite: i.e., processing ease for situation-predictable content (e.g., chopping carrots with a knife). Comprehenders are known to deploy knowledge about situation plausibility during processing in fine-grained context-sensitive ways. Using self-paced reading, we test whether comprehenders can also deploy this knowledge in favor of newsworthy content to yield informativity-driven effects alongside, or instead of, plausibility-driven effects. We manipulate semantic context (unusual protagonists), syntactic construction (wh- clefts), and the communicative environment (text messages). Reading times (primarily sentence-finally) show facilitation for sentences containing newsworthy content (e.g., chopping carrots with a shovel), where the content is both unpredictable at the situation level because of its atypicality and also unpredictable at the word level because of the large number of atypical elements a speaker could potentially mention. Our studies are the first to show that informativity-driven effects are observable at all, and the results highlight the need for models that distinguish between comprehenders' estimate of content plausibility and their estimate of a speaker's decision to talk about that content.