Universal processing biases versus cue cost and competition in how Italian children learn to understand transitive sentences.

Some ‘universalists’ claim that children initially interpret the first ‘argument’ (noun or pronoun) of a sentence as the agent (or ‘do-er’) of an action. Emergentists argue acquisition order is determined by formal ‘cues’ to the agent. These ‘cues’ can include word order (e.g. whether the agent comes before or after the verb) or case- marking (e.g. English ‘he’ indicates the agent) The emergentist view claims that learnability of a cue depends on ‘cue validity’ (the product of input frequency and cue reliability), its working memory ‘cost’, and competition between cues. Italian, where the agent is frequently omitted is problematic for both theories. Study 1 analysed 13229 utterances in Italian child-directed-speech (CDS) to calculate cue validities for word order and case-marking. In study 2, Italian preschoolers heard novel verbs in the three most frequent word orders in CDS. They had to choose between two video clips (e.g. horse acting on cat versus cat acting on horse). Contrary to universalist claims children did not reliably interpret the first argument as the agent until 4 1?2. In line with emergentist views, they relied on the ‘low cost’ case cue, but only when it did not compete with the highly valid word order cue.