Why cheat?

The unfolding saga of doping allegations against Lance Armstrong, the cancer-conquering cyclist who's been stripped of his record seven Tour de France titles, is putting international attention on cheating that hasn't been seen since, perhaps, Tiger Woods.

The alleged cheating in both cases is different. Woods' cheating was marital, resulting in divorce. Armstrong's alleged cheating bears upon athletic performance, putting his reputation and that of the U.S. team on the line.

Sports and marriage aren't the only realms for the cheat. Academia, workplace, science -- they are theaters for the misconduct, too.

Whether on a scale large or small, by someone who's in survival mode or who seemingly has it all, cheating is a frailty shared by all of us, experts in psychology and ethics say.

Have you ever cheated?

It's not a question that an ethicist likes to answer, especially when his nickname is "The Ethics Guy" and he does public speaking for a living.

But Bruce Weinstein, author of "Is It Still Cheating If I Don't Get Caught?" has been confronted with the question in talks before high school students.

"Inevitably, I'm asked whether I cheated," said Weinstein, who received his doctorate in philosophy from Georgetown University. "If I say I never cheated, they say, 'you're lying.' And when I say I did, then they say, 'Why should I listen to you? You're a cheater!'"

Honesty is paramount, Weinstein said.

"When you tell them the truth, they respect you more," Weinstein said. He once cheated in a high school physics class by trying to copy from the valedictorian's lab book, but stopped when the student gave him a "horrible" look, he said.

"I'm not sure I'm going to volunteer it, but if you ask me, I'll tell you," Weinstein said. "Maybe you can learn from my mistake."

CNN's Dr. Wendy Walsh, who holds a doctorate in clinical psychology, admits to cheating, too: When late for an appointment, she blamed traffic.

"Here's the important piece: Even good people cheat," Walsh said. "All human beings lie, even if it's a white lie: Oh, you look great in those jeans!

"But when it is a grave rule violation that is socially, completely looked down upon or there is a legal consequence," Walson added, "that's where it becomes a little more dicey, when we say, 'Where are the morals and values of the person?'"

In general, why do people cheat?

"There are a couple of ways to answer that question," said Paul Root Wolpe, the director for the Center of Ethics at Emory University.

"On the one hand, people tend to cheat in response to desires and incentives they want. There is individual motivation," Wolpe explained. "And then there are structural pressures, when they feel under pressure for their careers or income."

Atmosphere and institutional culture factor into whether cheating is accepted, said Wolpe.

In sizing up possible influences on cheating, Wolpe asks "is there a strong sense of ethical expectations?" or "is there a wink and a nod that we need to win at all costs?"