Two-year-olds' mapping of emotion words to facial expressions in a looking-while-listening task

Children's acquisition of emotion words is a topic of interest across the domains of emotion research, early language acquisition, and social development. Prior research has shown a slow, gradual process of emotion word acquisition during ages 2–5 years and beyond. However, this research has used tasks that are demanding for young children, such as asking them to label or sort facial expressions. Here, in a preregistered study, we used a child-friendly looking-time paradigm---the "looking-while-listening'' task---to assess children's understanding of four emotion words, "happy," 'sad," "angry," and "scared." We presented 64 two-year-olds (Mean age = 2.51, range: 2.00-2.97) with facial expressions and measured their preferential looking to the target face upon hearing an emotion word. Both younger and older two-year-olds showed above-chance performance when the target and distractor faces differed in valence (e.g., happy vs. sad). When the target and distractor faces were of the same valence (e.g., angry vs. sad), younger two-year-olds' results did not reach significance, but older two-year-olds' results were significantly above chance. These results suggest that within-valence mappings of emotion words to facial expressions emerges at least during the second half of age two.