At what age does infancy begin?

Infancy begins at 0 years old, which marks the stage of development when a baby is born. This period of growth and change continues until the child reaches approximately 1 year old. During infancy, there are significant developments that occur, including physical growth, sensory abilities, and early attachment forming with caregivers. The focus is on survival, basic needs, and the development of foundational skills that are crucial for future growth.

The other ages listed do not correspond to the definition of infancy. For example, 1 year old marks the transition from infancy to toddlerhood, a period characterized by different developmental milestones such as walking and speech development. Therefore, acknowledging that infancy encompasses the very beginning of life at birth is essential in understanding this critical early stage of human development.