When children see a rival contending for a caregiver's attention, the children try to get close to the caregiver and capture the caregiver's attention. Attempts to get close to the caregiver and capture the caregiver's attention indicate the attachment system has been activated. But the presence of a rival also provokes jealousy in children. The jealousy provoked by a sibling rival has been described in detail. Recent studies have shown that a rival can provoke jealousy at very young ages. The presence of a rival can provoke jealousy in infants as young as six months old. Attachment and jealousy can both be triggered in children by the presence of a rival.