Why do newborn babies humans have such small brains?

Newborn human brains are relatively small due to evolutionary adaptations that prioritize safe childbirth and maternal health. The human pelvis has evolved to accommodate bipedal locomotion, making it narrower, which limits the size of the baby's head at birth. Additionally, a smaller brain at birth allows for rapid postnatal growth and development, enabling the brain to adapt to environmental influences and experiences during early life. This balance of size and adaptability is crucial for survival and development.