Developmental Milestones: Stranger Recognition and Separation Anxiety
The correct answer is A (6 months), as this is when infants typically begin developing stranger recognition and separation anxiety becomes prominent.
Key Developmental Timeline
During the sensorimotor period (birth to 2 years), infants develop object permanence—the awareness that people and things continue to exist even when out of sight—which is fundamental to both stranger recognition and separation anxiety. 1
Stranger Recognition Development
- Infants generally begin to recognize strangers and emotional expressions after 6 months of age, with some studies documenting differential responses to unfamiliar persons by 7 months 2, 3
- By 6-7 months, infants can discriminate between different types of strangers using both facial configuration and height cues 2
- One-year-olds (12 months) show the greatest distress responses to strangers compared to other age groups, indicating peak stranger anxiety during this period 4
Separation Anxiety Development
- Minimization of separation from parents is of paramount importance during the sensorimotor period, as separation creates considerable anxiety in infants and young children 1
- The preoperational stage (2-7 years) is characterized by significant separation anxiety, but this anxiety begins developing earlier during the sensorimotor period 1
- Separation from primary caregivers can make a child more vulnerable and poses a threat to mental health, with children developing feelings of sadness, anxiety, and fear of being isolated 1
Clinical Context
Sense of Individuality
- The development of object permanence during the sensorimotor period represents the infant's emerging sense of individuality and understanding that they are separate from their caregivers 1
- This cognitive milestone typically consolidates between 6-12 months of age 5
Developmental Trajectories
- Stranger fear shows variable developmental trajectories, with some infants exhibiting stable high levels from 6 months onward 6
- Chronically high levels of stranger fear and sharp increases over time are linked to greater behavioral inhibition 6
Common Pitfall
The question describes behaviors that emerge during the late sensorimotor period (around 6-12 months), not later developmental stages. While separation anxiety intensifies during the preoperational stage (2-7 years), the initial recognition of strangers and fear of separation begins much earlier at approximately 6 months 1, 2, 3.