It starts with naps that the younger notices are not being taken by the older child.

Then for years, the torture of hearing the television voices muffled and unintelligible except enough to be annoying through the bedroom walls where one lies alone and sleepless apart from all other family members laughing and eating ice cream (oh, I'm sure they are!) in front of the tv.

These hour-or-longer separations which are never spent in sleeping anyway are the most traumatic for the child, and vary only by distance once the time has been adjusted more equally.