In a commencement address delivered at his alma mater, Dartmouth College, Fred Rogers, the late producer and host of the popular children's TV program, Mister Rogers' Neighborhood, asked the crowd of newly minted graduates to try an extremely simple but remarkable exercise. In recognition of someone?--a teacher, a relative, a friend?--who had shaped their lives, he asked everyone assembled to take a minute to silently think about the person, and the impact they had had on them: 

"Wherever they are, if they've loved you and encouraged you and wanted what was best in life for you, they're right inside yourself. And I feel that you deserve quiet time on this special occasion to devote some thought to them, so let's just take a minute in honor of those who have cared about us all along the way."

It's a moving scene, and I challenge anyone watching him say these words to not pause a moment and start reflecting on at least one person who has had a major influence on their life.

Cultivating a sense of inner gratitude can be inspiring and therapeutic. Expressing gratitude toward others can have a similarly positive impact on the recipient, as anyone knows from the expressions of delight that an emailed or hand-written "'thank you" can evoke.

And now, a new study published by two US psychologists in the journal Psychological Science provides clinical proof of what many of us already knew: Saying "thank you" can positively transform your relationship with others. 

In their research, as reported by the website of the British Psychological Society and The New York Times, Amit Kumar at the University of Texas at Austin and Nicholas Epley at the University of Chicago Booth School of Business asked participants to write an email to thank someone who had touched their life in a meaningful way, and express what that person had done and how they had affected their life. 

They also asked participants to predict how the recipient would feel and perceive them. The researchers then made contact with the recipients to find out how they actually felt.

One of the more surprising findings from their research was the gap in perceptions between the senders of the thank-you letters and the recipients. The senders consistently underestimated how positive the recipients felt about receiving the letters and how surprised they were by the content. The senders also overestimated how awkward the recipients would feel after receiving their notes. And they underestimated how warm, and especially how competent, the recipients perceived them to be. 

But after receiving thank-you notes and filling out questionnaires about how it felt to get them, many recipients said they were "ecstatic," scoring the happiness rating at 4 of 5. The senders typically guessed their note would elicit just a 3.

Kumar and Epley's research also showed how doubt among the senders of thank-you letters affected their willingness to write such notes. Participants who questioned their own ability to craft a thank-you letter?--?perhaps out of self-consciousness toward their writing skills, for example?--were less willing to send one. And doubt around the perceived impact on recipients made senders less willing to write one. 

So what should you do?

Cast aside your doubts and go ahead and write that thank-you email (or if you want to add a more powerful personal touch, deliver it via a handwritten note) you've been meaning to send to that person who has helped you or has had a positive impact on you recently?--?or even at a pivotal moment earlier in your career or your personal life.