Final answer:
Baby Henry is exhibiting avoidant attachment behavior when he does not react to his mother leaving, indicating that his caregiver may have been insensitive and inattentive to his needs.
Step-by-step explanation:
According to Ainsworth's studies on infant attachment, if Jocelyn leaves her baby Henry in a room and he does not react or show much emotion when she leaves, then Henry is exhibiting avoidant attachment behavior.
This kind of attachment is characterized by the child being unresponsive to the parent, not using the parent as a secure base, and showing no preference between the parent and a stranger.
Ainsworth found that such behavior is often the result of having a caregiver who was insensitive and inattentive to the child's needs, suggesting that the caregiver's behavior is a significant factor in the development of avoidant attachment.