Intonation facilitates contrast resolution: Evidence from Japanese adults and 6-year olds

► This study investigates online processing of contrastive prosody in Japanese adults and children. ► Participants’ eye movements were monitored during a visual object detection task. ► Adults processed prominence contrastively, but children needed longer time to update discourse. ► Prosodic processing develops gradually. Two eye-tracking experiments tested how pitch prominence on a prenominal adjective affects contrast resolution in Japanese adult and 6-year old listeners. Participants located two animals in succession on displays with multiple colored animals. In Experiment 1, adults’ fixations to the contrastive target (pink cat→GREEN cat) were facilitated by a pitch expansion on the adjective while infelicitous pitch expansion (purple rabbit→ORANGE monkey) led to a garden-path effect, i.e., frequent fixations to the incorrect target (orange rabbit). In 6-year olds, only the facilitation effect surfaced. Hypothesizing that the interval between the two questions may not have given enough time for children to overcome their tendency to perseverate on the first target, Experiment 2 used longer intervals and confirmed a garden-path effect in 6-year olds. These results demonstrate that Japanese 6-year olds can make use of contrast-marking pitch prominence when time allows an establishment of proper discourse representation.