[myth_drannon]

More than parents which are attached to the child with hormones, the smile is for the strangers so they do not harm them. At some stage babies smile all the time to strangers. That's before they get older and understand the concept of parents vs strangers.

[dingaling]

Cross-species, the opposite of 'smile at strangers' that I had to learn was when handling distressed dogs.

To a human a smile is cute, to a dog it is baring of teeth in a challenge.

[stevekemp]

Our baby is a fascinating example of this - every time he sees a stranger he makes a big smile.

He seems to just love people, and because of his big eyes and big smile it is rare that I can take him shopping, or for a walk, without at least one stranger talking to me about how happy he looks.

[seanmcdirmid]

Ya, same here, though it seems to be tapering off after 1.

[sitkack]

I got smiled at by a 9 month old on the plane just yesterday, the subtext was, "please don't eat me or my family."

[bonesss]

... don't leave us hanging, what did you do?

Did you let the infant assert dominance, or did his parents learn a lesson about the social hierarchy?