Stoic philosopher Epictetus once wrote, "He is a man of sense who does not grieve for what he has not, but rejoices for what he has."

If you want to be truly healthy and happy you can choose to give thanks each day, much as you might inculcate meditation or exercise into your routine. This is not just sentimental pablum, but scientifically supported fact.

Note the work and insights of Dr. Amy Cuddy of Harvard. Cuddy posits that tiny tweaks to our physicality can lead to mighty changes in our life and leadership. She believes that nonverbals govern how we think about ourselves and the larger world. For example, you can hold a pencil in your mouth in a way that artificially recreates a genuine smile. Odd as it may seem, forcing your face into a gesture of happiness actually makes you feel happy.

Of course, this does not mean we should all be walking around staring at each other with death's head rictus of smiling inanity. But growing scientific evidence suggests we can control and manipulate our feelings and mood--that we are not simply at the mercy of our circumstances or genetic inclinations. In other words, acting "as if" can actually create positive emotion.

I think one of the most useful of personal and business emotions is gratitude. (Note my Inc. Magazine column of last week titled "Thanksgiving and the Power of Gratitude in Business.")

Arthur C. Brooks, President of the American Enterprise Institute, wrote an insightful article on Sunday in The New York Times headlined "Choose to be Grateful. It Will Make You Happier." He suggests that acting gratefully, regardless of your feelings, is efficacious for both your interior state, as well as your external interactions. He notes a famous 1993 experiment "where researchers asked subjects to smile forcibly for 20 seconds while tensing facial muscles, notably the muscles around the eyes called the orbicularis oculi (which create 'crow's feet'.) They found that this action stimulated brain activity associated with positive emotions."

Brooks goes on to report, "According to research published in the journal Cerebral Cortex, gratitude stimulates the hypothalamus (a key part of the brain that regulates stress) and the ventral tegmental area (part of our 'reward circuitry' that produces the sensation of pleasure)."

Brooks also shares an illustrative episode fom his personal life which occurred in response to one of his recent books. Brooks recounts:

"One afternoon I received an unsolicited email. 'Dear Professor Brooks,' it began. 'You are a fraud.' That seemed pretty unpromising, but I read on anyway. My correspondent made, in brutal detail, a case against every chapter of my book. As I made my way through the long email, however, my dominant thought wasn't resentment. It was, 'He read my book!' And so I wrote him back--rebutting a few of his points, but mostly just expressing gratitude for his time and attention. I felt good writing it, and his near immediate response came with a warm and friendly tone."

So, many thanks today for Thanksgiving's reminder of the practical value of gratitude in everything we do. As Ralph Waldo Emerson puts it, "Cultivate the habit of being grateful for every good thing that comes to you, and give thanks continuously. And because all things have contributed to your advancement, you should include all things in your gratitude."

And thanks to you, Ralph Waldo Emerson.