Individual differences in young children's iconic gesture comprehension

Children learn a language with its multimodal aspects. However, iconic gestures emerge relatively later than other language forms, such as first words and pointing gestures. Previous research demonstrated that children begin to comprehend iconic gestures later than the age of 2. Although the literature indicates high individual variations in iconic gesture development among young children, the possible underlying factors that lead to individual differences in early language learning are understudied. In two studies, we investigated internal and external sources of young Turkish-learning children that can be associated with early iconic gesture comprehension. In Study 1, children between 22– and 30-month-olds were asked to choose the correct picture matching the experimenter's speech and iconic gestures and administered a receptive vocabulary test. We found that children performed better in the gesture comprehension task as they aged, and their performances were related to the receptive vocabulary knowledge. In Study 2, with a subset of children from Study 1, we investigated the role of expressive vocabulary knowledge, executive function performance, and parents' and children's iconic gesture production on children's iconic gesture comprehension scores. Results showed that only expressive vocabulary knowledge was related to children's iconic gesture comprehension after controlling for age, executive functions, and parents' and children's iconic gesture production. Overall, these findings suggest that Turkish-learning children comprehend others' iconic gestures better as they aged between 22 and 30 months, and their vocabulary knowledge is one of the best predictors of their iconic gesture understanding.