LONDON – The Harvey Weinstein sexual assault scandal shows no sign of winding down. Just the opposite: Police in the United Kingdom are now investigating several allegations involving the Oscar-winning film producer.

While Weinstein has “unequivocally denied” allegations of nonconsensual sex, and no arrests have been made, more than two dozen women – including Angelina Jolie, Gwyneth Paltrow, and Rose McGowan – have publicly accused him of harassment. The allegations stretch over nearly three decades.

Hollywood is struggling to explain how one of its most visible figures could have gotten away with such behaviour for so long. Woody Allen offered an important clue. Despite working with Weinstein on several films, he claims that no one ever brought allegations of abuse to his attention. “And they wouldn’t, because you are not interested in it,” Allen told the BBC. “You are interested in making your movie.” Others who worked with Weinstein over the years have made similar statements.

Is this the Hollywood equivalent of a police officer’s “blue wall of silence,” or is there something more clinical at work?

One possible answer may be found in the results of recent psychological research. According to scientists in the United States and Israel, there are certain personality traits-the “dark triad” of narcissism, psychopathy, and Machiavellianism-that are more commonly associated with sexually abusive behaviour.

One intriguing finding from this research, published in 2016 in the journal Personality and Individual Differences, is that personality traits associated with a proclivity for harassment may be “specialised psychological adaptations” that allow individuals to exploit “niches” in society. In other words, some sexual predators may seek careers in particular industries that allow them to exploit others.

Researchers also found that the disposition that makes someone successful may also comprise the personality traits that explain their tendency to exploit. The traits needed to win Academy Awards, for example, may be similar to the traits of an individual who pursues a large number of sexual partners and relationships requiring little commitment.

Taken a step further, the research suggests that we should not be surprised to find a similar parallel in many other corners of society. It is not just in Hollywood where the traits that make someone a star could make the same person an abuser.

The “dark triad” study was published long before allegations against Weinstein came to light, but it remains the most comprehensive investigation into the personalities of sexual harassers. The researchers-based at Oakland University and the University of Georgia in the United States, and Sapir Academic College in Israel-surveyed more than 2,500 Israeli men and women. Subjects prone to exploiting others demonstrated a number of characteristics, including callousness, disagreeableness, deceitfulness, egocentrism, lack of honesty or humility, and an excessive interest in one’s personal talents and goals.

This last trait – also known as narcissism-is a key component of the dark triad. Narcissists tend to be convinced of their own magnificence, and believe that other people should be flattered to be in their company – even if that involves unwanted sexual advances.

Machiavellians, meanwhile, believe that the best way to interact with others is to tell them what they want to hear. Their manipulative default can lead to a pattern of continually deceiving colleagues and friends, which may explain why a Machiavellian personality would engage in sexual harassment or pursue short-term sexual encounters. They simply believe they are too cunning to get caught.

When abusers are unmasked, they often seek to deflect blame. Claiming to be suffering from a disorder such as “sexual addiction,” or checking into a rehabilitation clinic for “treatment,” as Weinstein has reportedly done, fits with a classic Machiavellian response.

If the allegations pan out, Weinstein would be an extreme example of a “dark triad” abuser.

And, as the authors of the 2016 study remind us, sexual harassment is not always about trying to secure sex. Rather, psychological drives – including the need to boost one’s sense of self-esteem, attractiveness, or masculinity – may be driving predators’ abuse of power in dominating or degrading others.

What may be particularly relevant to the Weinstein case, whatever the outcome, is that Hollywood is itself a bubble of narcissistic power.

Sexual harassment is the immediate focus of the Weinstein case, as it should be, given the severity of the alleged crimes and the distress caused to the victims. But for psychologists seeking to understand the apparent nexus of success and abuse, Weinstein’s apparent downfall is just the tip of an analytic iceberg. 

Raj Persaud and Peter Bruggen are psychiatrists based in London, and co-authors of the forthcoming book “The Streetwise Person’s Guide To Mental Health Care.”

WASHINGTON – David Letterman, a pioneering entertainer who was the longest-running host of late-night TV in US history, was honoured on Sunday for his contributions to American culture.

After-hours television was built around the set-piece interview and guest appearance when Letterman’s “Late Night” broke the mould in 1982 with absurd pranks and send-ups.

Everyday viewers went on his show to present “stupid pet tricks.” Behind his desk, Letterman could be serious, dry and cerebral. But he often volunteered for oddball pranks. In one well-known stunt, he worked a shift at a Taco Bell in suburban New Jersey, taking pickup orders.

In another sketch, Letterman was dunked in water while covered in Alka Seltzer tablets.

Receiving the Mark Twain Prize for American Humor at the Kennedy Center, the national showcase for arts, Letterman, 70, was praised for his imagination, comic daring and heart.

Many younger comedians, including current late-night host Jimmy Kimmel, have described Letterman as a major influence.

Before Kimmel’s on-stage tribute to Letterman, the entertainer recalled one of his favourite, offbeat moments.

“Dave brought this doorknob out. And he put it on a table. And he said ‘It’s just plain big.’ That was it.” Letterman hosted more than 6,000 episodes of his original”Late Night with David Letterman” on NBC and its successor on CBS, “Late Show with David Letterman,” which ended its run in May 2015.

He won multiple Emmy Awards, US television’s highest honour, for his work as a writer, performer and producer.

The Indiana native made his first of 22 appearances on “The Tonight Show Starring Johnny Carson” in 1978. After hosting”Late Night” for 11 years, he moved to CBS in 1993 after losing out to longtime rival Jay Leno to succeed Carson at “The Tonight Show”.

On Sunday, comic friends teased Letterman about his late-night wars with Leno and retirement but the honoree struck a poignant note in his acceptance speech.

“Mark Twain’s definition of patriotism is this: Patriotism is supporting your country all the time and your government when it deserves it.” In 2012, Letterman was recognised for his contributions to the arts and American culture at the Kennedy Center Honors, a lifetime achievement awards for performing artists.

The Letterman tribute will be aired on public television stations on Nov. 20.