A social smile differs from a reflexive smile in that a social smile

• A. is unrelated to emotional development in infants
• B. is triggered by external social stimuli, such as seeing a human face
• C. is present at birth and does not change with development
• D. occurs in response to internal physiological changes only

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the definitions of the two types of smiles. A reflexive smile is an automatic, involuntary smile that typically occurs in response to internal physiological states, such as during sleep, and is present from birth.
2. Step 2: Recognize that a social smile is different because it is a deliberate response to external social stimuli, such as seeing a human face, and usually emerges later in infancy as part of social and emotional development.
3. Step 3: Identify that the social smile is linked to social interaction and communication, indicating the infant's growing awareness of and engagement with their environment.
4. Step 4: Compare the options given: the social smile is not unrelated to emotional development; rather, it reflects social and emotional growth. It is not present at birth but develops over time. It is triggered by external social stimuli, not just internal physiological changes.
5. Step 5: Conclude that the correct distinguishing feature of a social smile is that it is triggered by external social stimuli, such as seeing a human face.