That millennial you're working with may be a jerk

Studies have shown that millennials in the workplace are seen as disproportionately entitled, and are willing to sacrifice work friends for a promotion, but new research shows that they are even more willing to lie to get ahead.

Millennials—defined as anyone between 19 and 36 years old—say they would take credit for someone else's work to get ahead more than five times as frequently as boomers, according to a new study by marketing firm DDB. The survey also revealed that millennials are more likely to self-identify as "workaholics" than their older colleagues.

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Explanations for these findings vary widely: Some experts say that millennials' willingness to take credit for others' hard work is further evidence of their entitlement and feelings of deserving to succeed, while others argue that the tough job market has engendered a ruthless streak in the youngest American adults.

"We know from other studies we've done that [millennials] feel entitled to get ahead, they say they deserve it and are special compared to Gen Xers and boomers," said Denise Delahorne, senior vice president, group strategy director, DDB Chicago, who worked closely with the survey. "Their desire is so strong that some would do something that is morally questionable, or wrong."

But this narrative of the entitled millennial may no longer be as true as it once was, said Dan Schawbel, author of "Promote Yourself: The New Rules For Career Success" and the founder of Millennial Branding, a research and management consulting firm. Instead, young American adults may have finally learned humility from the current economic climate, he explained.

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"It's harder to feel entitled because it's harder to get a job in the first place," Schawbel said. "There's no way you can feel entitled when you're living at home."

It should be noted, however, that a study from last week confirms the entitlement narrative: 65 percent of respondents described millennials as "entitled," and 71 percent said they were "selfish."

Instead, millennials may have received a "huge wake-up call" from the estimated 40 percent unemployment rate among America's youngest adults, Schawbel said.

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"People who are young are working hard at their jobs, and are conscious of the fact that many peers don't have jobs," Delahorne said, acknowledging that a survey of working millennials may include some selection bias for more ruthless individuals. "They had to work harder to get the jobs they have."

Self-Description	Millennials	Gen Xers	Boomers
I'm a workaholic	44%	41%*	35%*
On a job, security is more important than money	61%	67%*	66%*
Work gives me my greatest satisfaction in life	45%	41%*	38%*
I would take credit for somebody else's work if it would help me get ahead	27%	15%*	5%*

As for the other major insight arising from the DDB survey, Delahorne said she found it surprising that a statistically significant difference arose between millennials and other generations in terms of workaholic self-identification. In the study, 44 percent of millennials said they fell into this category, compared to 41 percent of Gen Xers and 35 percent of boomers—defined as those aged 37-48 and 49-67, respectively.

"It makes me wonder if they understand as a cohort what workaholic means," Delahorne said. "As a boomer I see that word as someone who has to work, someone who always feels the compulsion to be working...maybe millennials just meant that it is someone who works a lot?"

But millennials may actually be harder workers on average than previous generations. John Challenger, the CEO of consulting firm Challenger, Gray & Christmas, said that his firm has seen that millennials stand out as employees who "work hard at what they're doing," despite not necessarily being tied down to specific firms.

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Ultimately, these traits may well payoff for the youngest American adults, for companies are looking for hard workers "more than anything else," Challenger said.

Still, millennials may not be as hard working as they think they are. Schawbel said his research has indicated that managers hold an overall negative view of the cohort, believing they have a "poor work ethic," and are "easily distracted."

The sample size for DDB's survey was 2,723 adults over the age of 18. The margin of error is plus or minus 1.2 percent, according to the firm.

—By CNBC's Everett Rosenfeld