Motivation: a smile?

While the one book I have says babies can't smile until about two months of age, another says some may smile around one month old. In the past week Brian and I have both seen what we think may be smiles. Not gas-smiles-while-he-sleeps, but actual upturned lips during the few moments he's awake and content. I tried to catch one this afternoon.

So we're calling them smiles, even if they're not yet, because this made the tough parts kinda worth it.