Typically, stranger wariness is first noticeable at:

The answer is 9 months. Characteristically, stranger wariness is first noticeable at 9 months. The stranger wariness is obvious as soon as an infant no longer smile at any welcoming face and cries if a new person moves too close, too rapidly. In addition, separation anxiety is expressed in tears and anger when the beloved caregiver leaves. The separation anxiety comes into view from 6 to 9 months of age, peaks around 14 months and then diminishes. The separation anxiety is a sign of the attachment of the child to the caregiver.   

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