During infancy, play involves exposing infants to sounds of varying volumes, objects to look at and touch, and helping them move their bodies. From birth to 3 months, infants' responses are largely undifferentiated and play is dependent. Pleasure is shown through quieting, smiling, and squealing. Recommended activities include presenting sounds to listen to, providing things to look at and touch within reach, and helping the baby move their body. This exposure helps stimulate infants' senses and motor development during this dependent early stage.