Researchers report men who feel stress over their perceived failure to live up to gender norms are at heightened risk of committing violent acts.

From Two and a Half Men to Donald Trump's recent put-down of Rand Paul as "weak," American pop culture has often contrasted two stereotypical images of masculinity: The hyper-masculine alpha male, and the borderline effeminate guy who lives in fear that others view him as unmanly.

The joke, of course, is how differently these two men act in the world. But newly published research suggests these caricatured figures have one troubling thing in common: they're more likely than most men to resort to violence.

This unexpected convergence can be traced to what a research team led by Dennis Reidy of the Centers for Disease Control and Prevention terms "masculine discrepancy stress." The "discrepancy" is between two sets of perceptions: How masculine a man feels, and how that self-image stacks up against societal expectations, at least in his own mind.

If a guy's perceived lack of macho cred gnaws at him emotionally ... watch out.

The researchers report failing to live up to society's definition of a manly man is not, in itself, a risk factor for violent behavior. But if a guy's perceived lack of macho cred gnaws at him emotionally ... watch out.

In their paper, published today in the journal Injury Prevention, Reidy and three University of Georgia psychologists present evidence supporting and refining the established link between violent behavior and threats to one's masculinity.

The researchers found that, in their sample, the odds of committing several specific types of violence—including assault with a weapon, and assault that leads to injury—were highest for men who felt they embody masculine norms, and were comfortable with that fact.

But—and this is their key finding—the odds of committing such crimes were nearly as high for a very different cohort of men: those who consider themselves less than truly masculine, and who feel tense or anxious as a result of that nagging perception. Some respond to this stress by acting out in a stereotypically masculine way: through violence.

The study featured 600 American males between the ages of 18 and 50, all of whom were recruited online. They responded to a series of statements reflecting perceived gender role discrepancy ("I am less masculine than the average guy"), and the stress that can result ("I worry that women find me less attractive because I'm not as macho as other guys"). Participants responded to each on a one-to-seven scale ("strongly disagree" to "strongly agree").

Subjects then answered questions about any substance-abuse issues, including how often they get drunk and/or use illegal drugs, and how many times they have ever been arrested for driving under the influence. Finally, respondents reported their lifetime history of violent acts, including the number of times they have been in physical fights; attacked someone "with intent to harm, injure, rape, or kill"; assaulted someone with a weapon; and intentionally hurt someone to the point they needed first aid.

Men who perceived themselves as less macho than most, and who felt anxiety or tension as a result, "reported rates of assaults causing injury 348 percent higher than men low on discrepancy stress."

Somewhat surprisingly, the researchers found no association between discrepancy stress and substance abuse. They did find that men who feel such stress acutely "reported the highest rate of arrest for DWI, which represents clear evidence of risk-taking conduct."

A clear link also emerged between such stress and violent behavior. To cite one specific finding: Men who perceived themselves as less macho than most, and who felt anxiety or tension as a result, "reported rates of assaults causing injury 348 percent higher than men low on discrepancy stress."

Participants who felt they didn't measure up to societal ideals of masculinity, but didn't really care, were the least likely to engage in violent behavior. They were also the least likely to drive while intoxicated.

In contrast, those at highest risk to either incur or inflict injury were "high-conforming/low-stress men" (guys comfortable with their perceived high level of masculinity) and "low-conforming/high-stress men" (guys uncomfortable with their perceived low level of masculinity). In other words, both pop culture stereotypes.

The researchers found relatively few men in their sample admitting to using violence; only 11 percent reported injuring another person in an assault. They point out, however, that a small number of violent men can cause major trauma for "individual victims and society as a whole," making the associations they have discovered potentially quite important.

Reidy and co-authors Danielle Berke, Brittany Gentile, and Amos Zeichner conclude that Americans need to take a serious look at "the means by which masculine socialization and acceptance of gender norms may induce distress in boys and men." Clearly, harmful messages about what it means to be a "real man" continue to be instilled in too many American adolescents.

This research suggests such indoctrination may lead to anti-social behavior—both for men who successfully embody the masculine ideal, and for those who fear they are failing to do so.

Findings is a daily column by Pacific Standard staff writer Tom Jacobs, who scours the psychological-research journals to discover new insights into human behavior, ranging from the origins of our political beliefs to the cultivation of creativity.