Article: Most people can fairly readily tell a forced smile from a real one, sometimes called the “Duchenne” smile after a pioneer in smile research. This is because the two use different muscles and different parts of the brain. But what exactly happens? What makes a real smile look “real”?  During a genuine smile, there is voluntary and involuntary contraction of two muscles: the zygomatic major and the orbicularis oculi, which raise the corners of your mouth and the areas around your cheeks and eyes, respectively. A forced smile only uses mouth muscles, however, because we cannot voluntarily contract the orbicularis oculi. This is why some people say a real smile uses the whole face, especially the eyes. Real smiles engage separates part of the brain, as well. While a forced smile uses the motor cortex, the real deal engages the limbic system, or the brain's emotional center. Like the rest of your body, your facial muscles will get better at their job if you exercise them often. They can be strengthened and toned through use, making it easier for you to flash your smile. Facial exercises and smiling can also make you look healthier and younger.  For a simple exercise, try a plain smile. Stretch the corners of your mouth laterally and hold for 10 seconds. Then, part your lips slightly and hold another 10 seconds. Repeat, even expanding your smile if you want.  Try this exercise to erase fine lines around your mouth: pucker your lips and suck in your cheeks, then try to smile. Hold this pose until the muscles start to tire. Do it once a day. Another exercise is the “silly rabbit.” For this one, smile as widely as possible without parting your lips. Then, try to wiggle your nose back and forth. This will engage the cheek muscles. Hold for 10 seconds and repeat. As said, a real smile does not just use the mouth and lips. It also engages the upper face, causing small crinkles around our eyes. In fact, this is probably the strongest give-away between a fake smile (using only the mouth and teeth) and a full, genuine one. A natural smile should light up your entire face.  Remember to lift your cheek muscles when smiling. Your eye brows may also be engaged and slightly raised. Try practicing in front of a mirror. As an added aid, cover your mouth so that only your eyes and eyebrows are visible. You should be able to “see” the smile only from your eyes. If you worry about fine lines around your eyes, consider ways to reduce the wrinkles other than keeping a strictly neutral expression. Smoking, lack of sleep, and exposure to the sun are much bigger culprits than smiles. Cut them out of your routine. You shouldn't have to sacrifice smiling. Flashing your smile in front of a mirror is a great way to practice. It will help you to discover what your natural smile looks and feels like, but also how to control it and use it to best advantage.  As children we're often taught to say “cheese!” for photos. Actually, “cheese” isn't great for a natural smile. Sounds that end with “ah” like mocha or yoga are much better at opening your mouth while slightly raising your cheekbones, looking more natural. Practice!  Pay attention to angles. Your face and smile might look better at certain angles than others. Experiment in the mirror. Find your best side. Then, use that angle in real interactions.  Some fashion models also use the following trick: touch your tongue to the roof of your mouth, just behind the front teeth. The movement should open your jaw very slightly and better define its lines when you smile.

What is a summary?
Know what makes a real smile. Exercise your smile. Learn to smile with your eyes. Practice with a mirror.