What is the term for the distress infants show when encountering new people?

Stranger anxiety is the term used to describe the distress that infants exhibit when they encounter unfamiliar people. This phenomenon typically emerges between the ages of six months and two years, coinciding with the developmental stages where infants become more aware of their surroundings and begin to differentiate between familiar and unfamiliar faces.

During this period, infants often exhibit signs of anxiety, such as crying, clinging to their caregivers, or displaying distress in the presence of strangers. This behavior is believed to be an evolutionary mechanism that promotes attachment to primary caregivers, ensuring the child’s safety and securing nurturing relationships.

Other terms listed in the options pertain to different aspects of emotional development or anxiety. For instance, separation anxiety refers to the distress felt by an infant or child when separated from their primary caregiver, while attachment anxiety typically relates to concerns in adult relationships. Social anxiety, on the other hand, is a condition characterized by intense fear and avoidance of social interactions, which is not restricted to a specific age group and often develops later in life. Thus, stranger anxiety is specifically identified with infants' responses to unfamiliar adults, making it the correct term for this context.