Titus reflects that, without the feed, their "heads felt real empty" (pg. 46). What is your response?

The teenagers' heads feel empty, because they are. Without the feed, these teenagers are completely unable to function as they are used to. They are used to talking without moving their mouths, and having their senses fed by things inside their own head. When that feed is gone, they are left with only their external senses, which are far less intense than things the feed can provide.