Three-month-old infant behavioral development chart and interpretation As the baby grows, its behavioral development is also constantly changing. Understanding the behavioral development of babies at three months can help parents better raise their babies. The following is a comparison chart and interpretation of the behavioral development of three-month-old babies to help parents better understand the growth of their babies. 1. Movement and posture A three-month-old baby can raise his head and stretch his back, turn his body while raising his head, and can straighten and bend his legs. Increasingly, they like to try to turn their heads towards