Sexual aggression against women has become commonplace in bars and nightclubs, a phenomenon that rises proportionately to a woman’s level of intoxication, a new study says.

"Recent data suggests that aggression related to sexual advances is very common nowadays," Kate Graham, a senior scientist at the Centre for Addiction and Mental Health at the University of Toronto, said in a statement.

In a study to be published in the journal Alcohol: Clinical & Experimental Research, Graham describes a field trip to nearby Windsor, Ontario, where she and her colleagues recruited bar patrons during a night on the town. After much revelry, participants were asked about two types of sexual aggression observed in the nightlife, including unwanted sexual contact and “unwanted persistence.”

More than 50 percent of women in the study reported experiencing at least one or both types of aggression that night.

Jeanette Norris, a senior researcher at the University of Washington who helped with the study, acknowledges the results as unsurprising. “Given the large number of young people who socialize together in bars, it is not surprising that a great deal of sexual assault occurs in bars,” she told reporters.

Yet researchers were surprised by the level of sexual aggression after initiating the study to learn more about conflict among men. "However, when we saw how much sexual aggression there was, we decided to conduct additional analyses,” Norris said. “So these analyses of sexual aggression were in response to how much we observed — which was considerably more than we were expecting."

Not surprisingly, the nightlife literally provides many sexual aggressors with the cover of darkness, providing a unique environment most people wouldn’t otherwise tolerate, or enjoy. Stripped of context, many behaviors observed in the typical bar scene would seem wildly out of place.

"I don't think you could get away with this sort of thing in most settings," Graham said. "If a stranger came up to a woman, grabbed her around the waist, and rubbed his groin against her in a university cafeteria or on a subway, she'd probably call the police. In the bar, the woman just tries to get away from him."

Psychologically speaking, the bar scene offers sexual aggressors — 90 percent of whom are men — with a sense of immunity from consequences, i.e., a “mob mentality.” With lowered social barriers in the boozy milieu of the late-night bar district, aggressors are also more easily able to dehumanize their target, the researchers said.

Aside from the night on the town, Graham and Norris compiled data on more than 1,000 incidents of interpersonal aggression observed during some 1,300 visits in 2000-2002 to 118 of Toronto’s hottest nightclubs. Of those conflicts, nearly a quarter involved sexual aggression.

"We found that while misperceptions in the making and receiving of sexual advances do occur, especially in the highly sexualized environment characteristic of many bars, most of it appeared to be intentional harassment or aggression done for the amusement or gratification of the person making the overture, or for the amusement of his friends," Graham said. "This interpretation is supported by the finding that sexual aggression was related to the intoxication level of the target but not for the aggressor.”

In other words, drunker women made for easier targets, the researchers concluded. Although short on originality, the researchers suggested a novel way for bar and nightclub owners to help lower rates of sexual aggression.

"It may help to avoid having male security staff who particularly endorse masculinity norms and asserting identity," Graham said.

Rather, owners might post signs prohibiting such behavior, with bar staff “trained” to intervene first with verbal warnings before asking the aggressor to leave. Failing that, masculine norms might be tolerated for a moment as bouncers toss the offender to the curb.

Source: Alcoholism: Clinical & Experimental Research. 2014.