Los Angeles, California - Twitter has become more hateful since Elon Musk took over the platform, new research has revealed.

According to data collected by researchers from USC, UCLA, UC Merced, and Oregon State University, daily use of hate speech by those who previously posted hateful tweets nearly doubled after Musk finalized the sale. And the overall volume of hate speech also doubled sitewide.

The research was conducted by Keith Burghardt, Matheus Schmitz and Goran Muric of USC, UCLA's Daniel Fessler, Daniel Hickey of Oregon State, and Paul Smaldino of UC Merced.

The group studied the tweets of users who had made hateful postings a month before and after Twitter was sold and also collected a sampling from the general user pool.

The researchers first developed a "hate lexicon" of 49 racist, antisemitic and homophobic and transphobic terms. Then, they examined the pre- and post-sale postings using an artificial intelligence tool that scanned for the hateful terms and their frequency, weeding out "non-toxic," or non-hateful, uses of the terms.

"We first had to create a set of words that we could determine as being hateful," Burghardt, a computer scientist with the Information Sciences Institute at the USC Viterbi School of Engineering, said in a news release. "Our aim was to find words that were relatively high precision, meaning that if people are using these words, it's unlikely they're being used in a non-hateful manner."

The volume of hate speech posted by hateful users surged after the sale was finalized, although researchers noted that hate speech on Twitter was on the rise even before Musk bought it.

At the outset of their project, the researchers hypothesized that, with Musk nodding toward less restrictive policies, hate speech would increase. But they were unsure by just how much.

"I didn't have any expectations one way or the other," Fessler, who is director of the UCLA Bedari Kindness Institute, said in an interview with The Times, "because it's very difficult to gauge in advance. You don't know what the population of users potentially producing such content is, you don't know what the size of the population is or what their frequency of tweeting and retweeting is."

But the results shocked Burghardt.

"What was surprising was ... that this stuff had increased so dramatically," he told The Times. "We had not expected that hate users would actually be using more hate words after Elon Musk joined Twitter."

Fessler noted that expressions of intolerance had been on the rise since the start of Donald Trump's presidential campaign, and that Musk "winked at those sentiments often enough that a population of active or potential Twitter users who shared those views recognized the opportunity they were being given."

"From a kind of 30,000-foot level," Fessler said, "the Twitter effect is really reflective of larger trends in society."

Researchers noted that they could not "prove a causal relationship between Musk's takeover and hate speech." The CEO's changes to moderation are "poorly documented," they said.

In the months that followed, he implemented several new initiatives at the company and the site, including firing hundreds of employees, reinstating hundreds of previously banned accounts, stripping verification badges from most users who did not pay $8 per month for a Twitter Blue subscription.