Adding a smile to your to-do list can ease the stress of multitasking.

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PROBLEM: Happiness makes us smile, but can smiling make us happy? Even if it's a fake smile, because your mouth is propped open by chopsticks? There's the standard smile, which remains located in the muscles surrounding the mouth, and the genuine (or Duchenne) smile, which spreads to the eyes and, at least anecdotally, both looks and feels warmer and more natural. Does one work better than the other?

METHODOLOGY: In an experiment that was smile-worthy in its own right, researchers used chopsticks to manipulate the facial muscles of their 169 participants into a neutral expression, a standard smile, or a Duchenne smile. In addition to the chopstick placement, some were explicitly instructed to smile. Then, they were subjected to a series of stress-inducing, multitasking activities, which they struggled to perform while continuing to hold the chopsticks in their mouths. The subjects' heart rates and self-reported stress levels were monitored throughout.

RESULTS: The participants who were instructed to smile recovered from the stressful activities with lower hear rates than participants who held neutral expressions, and those with Duchenne smiles were the most relaxed of all, with the most positive affect. Those with forced smiles held only by the chopsticks also reported more positive feelings than those who didn't smile at all.

CONCLUSION: When a situation has you feeling stressed or flustered, even the most forced of smiles can genuinely decrease your stress and make you happier.

The full study,"Grin and Bear It: The Influence of Manipulated Positive Facial Expression on the Stress Response," is published in the journal Psychological Science .

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