William Sears states that any sleeping arrangement that a family practices is acceptable as long as it works; but he advises mother to sleep close to the child.[51] He thinks of co-sleeping as the ideal arrangement and refers to it as the nighttime equivalent of babywearing: co-sleeping supports, in his opinion, the mother-child-attachment, makes breastfeeding more convenient, and prevents not only separation anxiety, but SIDS, too.[52] Sears is convinced that mother and child, in spite of frequent nighttime breastfeeding, have the best sleep when they sleep close together.[53] He is also convinced that due to the extra nighttime feedings, a child that sleeps close to the mother thrives better than a child "crying, alone, behind bars".[54] Moreover, Katie Allison Granju argued that co-sleeping is beneficial for children, too, because it gives children a vivid notion of the concept of bedtime.[55]