The largest graduating class in Greens Farms Academy history was exhorted Thursday by commencement speaker Scott Pelley, anchor of "The CBS Evening News," to find the thing that makes their hearts sing and follow it.

"Find that thing that gives you joy, find that thing that you'd do even if they didn't pay you to do it," said Pelley, whose daughter Blair was among the 83 graduates to receive diplomas Thursday morning on the grounds of the Westport private school, attended by many Fairfield students. "And those people, and there will be some, who tell you no, that's the wrong thing? They just don't hear the song."

Pelley, who also serves as a correspondent for the CBS news magazine program, "60 Minutes," said the 2013 graduates are going to take "the test of humanity" every day of their lives.

"And when the question is prejudice, answer justice. And when the question is poverty, answer compassion. And when the question is challenge, answer courage."

Pelley, who has been stationed all over the world as a news and war correspondent, said graduates should not look at their diplomas as a piece of paper, but rather as a ball.

"We're giving you the ball. You have to run with it now," Pelley said. "We need you. We can't say what the challenges are going to be for our country in your lifetimes, but this we know: There will challenges, there will be great challenges. So who is going to meet those challenges? Don't look up here. We're old. That's what this has been about, this education of yours."

Another first in GFA history -- a tie between two graduates named as valedictorian --had Rashad Nimr and Caroline Vanacore sharing the dais. They went back and forth in describing how the effort to define members of their class with single-term designations was a futile exercise.

"We cannot define ourselves by one single attribute and neither of us have taken a straightforward path to where we are today," said Vanacore, a Darien resident who will attend Dartmouth College in the fall.

Nimr, who has a stutter, said he has found a voice in his many pursuits.

"As a stutterer, I have found solace in the areas that have allowed me to have a voice," said Nimr, a Fairfield resident who will attend the University of Pennsylvania. "I sing to be heard, I act to empathize, I write to speak, I play squash to compete, I study languages to interact, math and science help me to understand, and yet there is no single path with which I identify."

They closed their joint valedictory speech by paraphrasing the closing speech from "The Breakfast Club," the 1985 John Hughes movie about teenagers grappling with their identities.

"Dear world, we accept the fact that we had to sacrifice several days to write this speech, but we think it would be crazy to write an essay telling you who we think we are. You all may see us how you want to see us. In the simplest terms, with the most convenient definitions, of what we've found out is that each one of us is a brain and an athlete and a basket case, a princess and a criminal. Does that answer your question? Sincerely yours, Rashad and Caroline."