We report a series of artificial language learning experiments designed to test child and adult learners abilities to acquirethree types of phonological variation. Previous work on experimental morphology (Hudson Kam & Newport 2005, 2009;Schuler, Yang & Newport, 2016) has found that young children turn inconsistent input into an invariant rule, while adultsreproduce and match variation in their input. Here we investigate whether phonological variation of three different types(deterministic conditioning, unconditioned variation, and probabilistic variation) exhibits a similar age pattern. We finda clear effect of age in grammatically-conditioned variability, with the youngest children showing a strong tendency toregularize to the stem form, adults probability-matching, and intermediate-aged children learning correct conditioning butnot matching the input probabilities. These results suggest, in accord with previous findings on morphology, that variationis not readily learned by young children and may instead be acquired as a separate process.

The spread of cultural variants, such as dress or speech pat-terns, may be promoted or inhibited by different types of bias.In model-based bias, variants are differentially adopted accord-ing to characteristics of individuals exhibiting them. A surpris-ing case of cross-group adoption comes from sociolinguisticfieldwork in which White speakers were observed exhibiting afeature of African-American Vernacular English, in spite of ex-pressing aggressively negative attitudes towards their African-American neighbors. A likely explanation for this is that thefeature in question had become dissociated for these speakersfrom the inalienable trait Blackness, but had retained associa-tions with the more alienable trait of being “street” or tough.We tested this by conducting an artificial-language experimentin which groups of four participants played a computer gamethat involved typing instant messages to each other, tradingresources, and fighting. Participants were assigned to one oftwo mutually antagonistic “alien species” (weaker Wiwos andtougher Burls) and learned an alien language with two species-specific dialects. In one condition, the Wiwos were told thatthat Burl dialect was mainly used by Burls; in the other con-dition they were told it was mainly used by “tougher aliens”.Burl variants were significantly more likely to be used by Wi-wos in the latter condition than in the former, even though theywere associated with tougher aliens in both conditions. Thissuggests that cultural variants linked to more alienable traitsare more likely to be adopted than those linked to inalienableones, even if the practical implications of the two traits are verysimilar.