Which of the following is most often considered atypical behavior in a 4-year-old?

• A. Engaging in whimsical play with toys
• B. Acting out or getting angry when upset
• C. Sitting alone, rocking, and arm flapping
• D. Thumb sucking and humming when tired

Answer: (C)

At around four years old, children typically engage with others, use language in social play, and show increasing flexibility in how they play and express emotions. Sitting alone, rocking, and arm flapping describe repetitive, self-stimulating movements and a tendency toward solitary activity, which are often considered atypical for this age. These patterns can be early signs of autism spectrum disorder or sensory processing differences, especially when frequent or persistent and interference with learning or social interaction is present.

In comparison, whimsical play with toys is a normal part of imaginative play, acting out or getting angry when upset can reflect typical emotional development and regulation, and thumb sucking with humming when tired is a common self-soothing behavior. Because the first pattern aligns with potential developmental differences while the others fit more typical variability, it stands out as the atypical behavior. This pattern would commonly prompt screening and, if indicated, further evaluation.