The Obligatory Contour Principle as a substantive bias in phonological learning

Understanding how native speakers acquire the phonological patterns in their language is a key task for the field of phonology. Numerous studies have suggested that phonological learning is a biased process: certain phonological patterns are more easily accessed and learned by the speakers and thus more likely to appear in languages, while others show acquisition difficulties and may occur less frequently. Therefore, an important aspect of understanding phonological learning and typology is to understand the nature of these learning biases. Obligatory Contour Principle (OCP), i.e., the avoidance of adjacent similar units in the lexicon, is one of the typologically well-attested phenomena that may originate from phonological learning biases. Using an artificial grammar learning experiment testing the learnability of several phonotactic patterns, we present evidence that the OCP can directly modulate phonological learning, in that similarity avoidance is easier to learn compared to other phonotactic patterns. Specifically, an OCP-based phonotactic pattern was better learned than a complexity-matching consonant major place harmony phonotactic pattern as well as an arbitrary control pattern. Based on the AGL experiment results and the phonetic foundation of similarity avoidance, we argue that the OCP can serve as a substantive bias that influences phonological learning and, eventually, linguistic typology.