When we’re comfortable with someone, we’ll tend to smile in a more genuine and spontaneous way. Smiling without showing our teeth is more of a forced smile.
This is backed up by a 2009 Dutch study, in which men were filmed performing posed smiles and spontaneous smiles, with the latter provoked by watching a funny film. When the researchers compared the two types of smile, they found that genuine smiles were both wider and toothier than posed ones.
- Why do we smile?
- Why do we have wisdom teeth?
- Are some things funny to all cultures?
- Why do jokes make us laugh?