Infants less than 18 months must achieve the Trust vs. Mistrust stage, in order to develop appropriately. A hallmark of this stage is having his or her needs totally met by a caregiver and developing trust in them. Therefore, “letting the baby cry it out,” places the infant in danger of not achieving this milestone, and it should be discouraged. Initiative vs. Guilt, Intimacy vs. Isolation, and Autonomy vs. Shame and Doubt are appropriate milestones for older individuals, not infants.