During infancy, babies undergo significant physical, sensory, and cognitive development. Their brains and bodies rapidly develop and change. Reflexes help with survival as motor skills and senses like vision, hearing and touch improve. Babies learn through classical and operant conditioning as well as observing others. They begin to categorize information and remember events. Language development starts with crying and cooing before advancing to babbling and understanding words. Temperament, attachment styles, and self-concept also emerge during this period of life. Non-parental care can impact development, though its effects are complex.