All smiles today

There are smiles, and then there are smiles. Also, 7 other things worth your time.

Smile, they say, and the world smiles with you.

But, there's more than one kind of smile, and I’d like to talk today about a study suggesting that nothing stresses people out like being smiled at the wrong way.

In fact, it turns out there's an immense power that can be leveraged behind subtle changes in your facial expressions.

First, we've all had the experience of being on the receiving end of a "fake smile," and perhaps becoming agitated by it. Think of a negative customer service experience, for example, in which the employee's facial expression conveys a sentiment that is the exact opposite of their behavior.

This study goes beyond that common experience, by measuring stress hormones in research participants whose reactions to various types of smiles were measured and judged.

It starts with the presumption that broadly speaking, there are three major types of smiles:

• Dominance smiles, which are intended to convey status,

• Affiliation smiles, which are intended to convey that you're un…