PORTLAND — Graduates at the University of Southern Maine were counseled to work hard and learn from rejection – and also turn off their cell phones and unplug their laptops from time to time.

Author Phillip Hoose, whose book, “Claudette Colvin: Twice Toward Justice” won the National Book Award for young readers last fall, led graduates in a rendition of “Bring Back the Eight-hour Day” to wrap up his USM commencement address at the Cumberland County Civic Center this morning.

Hoose also sang “Hey, Little Ant,” a song he co-wrote with his daughter, Hannah Hoose, which inspired his first book.

Hoose noted that “Hey, Little Ant” – an imaginary conversation between an ant and a child who is considering whether to stomp the insect – was initially rejected by dozens of publishers. Two years ago, it surpassed a million copies sold, he said.

“No project ever taught me so much about how to work,” Hoose said about the process of convincing a publisher to take on the book. He said rejection at first got him down, but he made a rule that gave him a day to be upset over the rejection and then he would re-read rejection letters to find ways to improve the proposal and eventually found a publisher.

The song, “Bring Back the Eight-Hour Day,” written by Charlie King, is a reminder that labor activists worked for decades to bring about the eight-hour workday but modern technology and productivity pressures are eroding that right.

USM graduated 1,200 students this spring.