One or Many? The Influence of Talker Variability on Infant Word Learning

We examined the impact of speaker variability on 19-month-old infants’ ability to learn word-referent mappings. Infants were randomly assigned to either a single speaker training condition (ST) where they learned word-referent mappings from voice recordings from one female or a multiple speaker condition (MT) where they learned the same pairings, but heard them labeled from voice recordings of eight females. Infants were tested on the mappings immediately following training and after a one-week delay. At test infants had to generalize the mappings to a new female voice and sentence not heard during training. Females in the MT condition demonstrated generalization of the mappings immediately after learning, but not at the delayed test. In contrast, females in the ST condition only exhibited generalization of the mappings at the delayed test. Males did not demonstrate word learning at either the immediate or delayed test, regardless of condition. Our findings suggest that high amounts of speaker variability promotes generalization of mappings immediately after training, but that lower variability benefits recognition after a delay, at least for females.