What is the primary purpose of infant crying in all cultures?

The primary purpose of infant crying across all cultures is fundamentally a form of communication. Infants are born unable to verbalize their needs and emotions, and crying serves as their primary means of signaling to caregivers. Through crying, infants convey various messages, including the need for attention, comfort, nourishment, and care.

This mode of communication is crucial for their survival, as caregivers learn to interpret the different sounds and patterns of crying to understand what the baby requires. For instance, a hungry baby may cry differently than one who is tired or in pain. Therefore, crying not only serves to express immediate needs but also helps to strengthen the bond between the infant and the caregiver, as the caregiver responds to these communications appropriately.

The other options, while they point to specific situations where infants may cry (like expressing hunger or signaling discomfort), do not encompass the broader concept of communication that crying represents. Each of those situations can be seen as specific instances of communication, but the overarching purpose remains the infant's need to communicate their needs and emotions to their caregivers.