The second year of an infant's life is when most parents are forcing their
kid to eat Neolithic foods. Following Hans Selye's characterization of
adaptation you have the stages of Shock, Adaptation, then Exhaustion. So my
theory is the terrible twos is the shock stage. If I am correct then a
paleo baby would not go through the terrible twos. For more discussion of
Selye see:

  http://www.GFlinks.com/hoggan/selye.txt

Don.