Final answer:
1-year-old Erik's lack of response to his mother's absence and return suggests he has an avoidant attachment style, where no secure base is established, and there is little to no preference for the caregiver over strangers.
Step-by-step explanation:
If 1-year-old Erik seems not to care when his mom leaves the room and shows no sign of noticing when she returns, Erik's attachment style could most likely be categorized as avoidant attachment. In the avoidant attachment style, a child does not use the parent as a secure base and shows no preference for the parent over strangers. These children often have caregivers who were insensitive and inattentive to their needs, leading to a lack of responsive interaction. By contrast, a secure attachment is characterized by children showing distress when caregivers leave and happiness when they return; children with resistant attachment show clingy behavior and can't be easily comforted on their return; and those with disorganized attachment exhibit odd or erratic behaviors when the caregiver returns. Erik's behavior suggests a lack of responsiveness associated with avoidant attachment.