Prediction is pervasive in human cognition and plays a central role in language comprehension. At an electrophysiological level, this cognitive function contributes substantially in determining the amplitude of the N400. In fact, the amplitude of the N400 to words within a sentence has been shown to depend on how predictable those words are: The more predictable a word, the smaller the N400 elicited. However, predictive processing can be based on different sources of information that allow anticipation of upcoming constituents and integration in context. In this study, we investigated the ERPs elicited during the comprehension of idioms, that is, prefabricated multiword strings stored in semantic memory. When a reader recognizes a string of words as an idiom before the idiom ends, she or he can develop expectations concerning the incoming idiomatic constituents. We hypothesized that the expectations driven by the activation of an idiom might differ from those driven by discourse-based constraints. To this aim, we compared the ERP waveforms elicited by idioms and two literal control conditions. The results showed that, in both cases, the literal conditions exhibited a more negative potential than the idiomatic condition. Our analyses suggest that before idiom recognition the effect is due to modulation of the N400 amplitude, whereas after idiom recognition a P300 for the idiomatic sentence has a fundamental role in the composition of the effect. These results suggest that two distinct predictive mechanisms are at work during language comprehension, based respectively on probabilistic information and on categorical template matching.

Several studies have argued that children under the ages of nine or ten years rarely comprehend figurative language and therefore interpret it literally. Cacciari & Levorato (1989). showed that when idioms are presented within a rich informational environment, children are able to grasp the figurative sense at the age of seven, and also that children are less able to produce idioms than to comprehend them. In three experiments involving 264 children (whose age ranged from 6;9 to 11;9), we contrasted this global elaboration hypothesis with a partially alternative one, the acquisition via exposure hypothesis, according to which the frequency of exposure of children to idioms is the main factor explaining their acquisition and production. Results showed that familiarity (i.e. frequency of exposure) plays a minor role and only for children who are not yet able to use contextual information. Familiarity per se does not adequately explain how children acquire a figurative competence. A tentative model is proposed in order to account for figurative competence acquisition.

We present a consensus-based checklist to improve and document the transparency of research reports in social and behavioural research. An accompanying online application allows users to complete the form and generate a report that they can submit with their manuscript or post to a public repository.