Rather than thinking of nature versus nurture it is better to think about interactions between genes and the environment. The Santa Barbara School of evolutionary psychology proposed that human cognition is the result of innately specified domain-specific mental modules. Babies have certain expectations of the way that the physical world operates. Infants of at least three months of age have the knowledge that objects exist independently of their ability to perceive them. Babies have preference for face-like stimuli from birth and learn the details of human faces rapidly. Young children have an understanding of the role of mental states as a cause of behaviour. This skill, known as theory of mind, becomes more sophisticated as children develop. It is measured by a number of tasks such as false belief task and the eyes test, in which participants are required to judge how people feel from looking at their eyes.

This chapter provides an exploration of brain development, with a strong emphasis on essential learning goals. We start with an infant born at term, where the foundational brain structure is already established, and most neurogenesis is complete by the end of the first postnatal year. However, childhood is a critical phase for brain development, marked by increased energy allocation. Our examination highlights the vital interplay between genes and the environment in shaping the brains trajectory. Neither can independently dictate outcomes; instead, brain development unfolds as a dynamic and adaptable process within genetic boundaries. We commence by introducing fundamental brain anatomy concepts, laying the foundation for a comprehensive understanding of development. Subsequently, we embark on a journey from the first neural cell to the newborn, elucidating the emergence, pathways, and connections of nerve cells. Finally, we summarize postnatal changes, drawing insights from histology and structural MRI, revealing the ongoing marvels of brain growth while remaining focused on our core learning objectives.