African-Americans love technology. They were early adopters of gadgets such as cell phones and have turned #blacktwitter into a powerful collective. But African Americans are sparsely represented in Silicon Valley.  And the numbers back this up.

According to TechCrunch, only 4 percent of Facebook’s 25,000 employees are Black. More than half of them are White. At Twitter, the number is 3.4 percent. Also, about 50 percent of Twitter’s workforce are White males.

California Rep. Maxine Waters and the Rev. Jesse Jackson have both challenged Silicon Valley companies to improve their diversity.

“Black people are greater users of the product and capable of doing the jobs, but there has not been an adequate commitment to hire, train and maintain [Black people],” said Jackson, during a Rainbow PUSH Coalition tech forum in 2015.

Altif Brown is a Silicon Valley veteran. He is co-founder and chief operating officer for Constellation Labs, a blockchain technology startup. The company raised $33 million in funding in January.

Brown has unique insights into working in Silicon Valley. He said the diversity problem is even worse when you get to the executive level.

“It’s no secret that there is a lack of diversity in the tech industry. It’s not restricted to black people either. Over 80 percent of tech executives are White, and most of them are men,” said Brown, who is a third-generation Silicon Valley native.

Brown said this “homogenous” culture can be difficult for African Americans to penetrate.

“This leads to very stark dissonance amid culture shock for many underprivileged people, both newly joining tech companies and communities that are overwhelmingly White. I was raised around a lot of diversity, and many of my friends were White, so wading into the tech scene was less of a culture shock than for some of my peers,” said Brown.

Brown says two keys to thriving in Silicon Valley, and tech, are opportunities and training. He’s pleased to see more African Americans are seeking training in Science Technology Education and Mathematics (S.T.E.M) courses, but that’s only the first step.

“I think that, recently, there has been more of an effort by tech companies, particularly startups, to ensure that their employees are not only qualified, but diverse,” he said. “However, in order for Black people to be hired, they have to be given the opportunity to both pursue the education to get there, as well as willing to put up with the uncomfortableness of being the only Black person in the room. The latter is not necessarily a ‘Black’ problem, but a culture problem.”

However, Brown said that you don’t necessarily have to move to Silicon Valley if you’re a techie with a great idea for a startup.

“I think that more people, in general, are looking for other areas to get into the tech field. The incredible cost of living, among a myriad of other factors, has caused an exodus of sorts. I understand why newcomers would – and are – pursuing tech opportunities in emerging tech hubs such as Atlanta, Seattle and Austin,” he said.

Kunbi Tinouye, who runs the Atlanta-based UrbanGeekz a blog about African-Americans in the technology field, agrees.

“Silicon Valley is a world-renowned tech hub. However, I’ve heard drawbacks include heavy traffic, a high cost of living and gender imbalance. I also know someone who completed grad school in Atlanta and then relocated to the Valley,” she said. “Within a few months, he moved back to Atlanta. His biggest complaint was the lack of diversity.”