Experiment 2 used a similar design to address whether 9-month-olds’ second-order correlation learning is facilitated by paired presentation of the test stimuli. Experiment 3 was designed to examine whether 7-month-old’s second-order correlation learning is affected by making the familiarization stimuli more distinct, and Experiment 4 was devised to explore the mental representations that 11-month-olds form during the process of second-order correlation learning.