Category-specific and system-wide preferences in competition: Evidence from noun phrase harmony

Typological data show a tendency for languages to exhibit harmonic (i.e. consistent) ordering between heads and dependents. Previous experimental work using artificial language learning experiments has shown that learners prefer harmonic patterns. This suggests that the typological trend for harmony may, at least in part, be driven by a cognitive bias. However, it is well-documented that specific categories sometimes contradict this tendency. Here we investigate one such case in the domain of the noun phrase. While many nominal dependents exhibit harmony, adjectives and genitives do not: adjectives tend to follow the noun and genitives tend to precede. Previous experiments have identified the existence of cognitive biases that keep these dependents split across the head noun in contexts where there is no conventional language system in place. In this study we use a silent gesture experiment to examine whether the specific biases that apply to these two dependent types compete with a general preference for harmony in an artificial language learning task. Specifically, we examine whether participants' learning behaviour is consistent with a preference not just for harmony, but for a non-harmonic order where adjectives follow and genitives precede the noun. What we find instead is that participants preference for harmony is not modulated by category-specific biases for prenominal genitives and postnominal adjectives. Thus when participants are learning a conventionalised system, the general bias in favour of harmony overrides category-specific preferences. We discuss the implications of this finding for explanations of typological tendencies which link them to cognitive biases.