From observing my own kids, I would say that difficult behavior (which can include tantrums) often precedes a developmental leap. I'm not sure why...if it's frustration or just that their mental (and physical) resources are being taxed while they master something new.
Hmm. This could mean that one of my kids (who shall not even be identified by DS or DD) was constantly mastering something new and being constantly taxed from age ~2 months to ~ 5 years. Especially when s/he was three.
Alternatively....
Val
