Pragmatic effects on semantic learnability: Insights from evidentiality

Cross-linguistically prevalent semantic distinctions are widely assumed to be easier to learn because they reflect natural concepts. Here we propose an alternative, pragmatic perspective that links both the cross-linguistic prevalence and the learnability of semantic distinctions to communicative pressures. We focus on evidentiality (the encoding of the speaker's information source). Across languages, grammatical evidential systems are more likely to encode indirect sources (especially, reported information) compared to direct sources (e.g., visual perception). On a conceptual account, this seems puzzling, since humans reason naturally about how seeing connects to knowing. On a pragmatic account, however, the predominant encoding of the speaker's reportative compared to visual information sources can be explained in terms of informativeness (visual access is ubiquitous and potentially more reliable, hence less marked). We tested the pragmatic account in four experiments. Adult English speakers exposed to novel miniature evidential morphological systems consistently showed higher learning rates for systems with a single indirect (reportative) compared to a single direct (visual) evidential morpheme (Experiment 1). This pattern persisted even when participants were given specific cues to the target meanings (Experiment 2) and partly extended to cases where evidential meanings were conveyed through visual, not linguistic, means (Experiment 3). It also persisted when the evidential morphemes had to be learned from different materials (Experiment 4). We conclude that the cross-linguistic bias to mark reportative/indirect over visual/direct sources of information has pragmatic roots that also shape the learnability of evidential semantic distinctions.