Age of acquisition for naming and knowing: a new hypothesis.

This paper reports an investigation into the age of acquisition of object names and object knowledge in a cross-sectional study of 288 children aged between 3 years 7 months and 11 years 6 months, comprising equal numbers of boys and girls. The objects belonged to four categories: animals, fruit and vegetables, implements, and vehicles. They were presented in three image types: line drawings, black-and-white photographs, and coloured photographs. In the knowledge test, five probe questions were asked for each object given the spoken name. Results showed that line drawings were more difficult to name than either black-and-white photographs or coloured photographs, which did not differ. The boys significantly out-performed the girls at naming and knowing, both overall and specifically for the category of vehicles. Naming and knowledge increased steadily with age but while young children below about 6 years 6 months showed an advantage to naming, older children showed an advantage to knowing. Similarly, age-of-acquisition measures for each item revealed a significant shift in the relationship between naming and knowing at around 80 months. We argue that differences in learning experience lead younger and older children to associate object names with different types of information, and we suggest that this difference probably accounts for the age-of-acquisition effects reported in adult object naming.