In a Q&A session at Facebook's headquarters in Menlo Park, California, CEO Mark Zuckerberg stoday said that Facebook would offer more choices than merely "like." He also discussed virtual reality and artificial intelligence. The company is planning to begin testing a new button that will expand the range of emotions users can express other than merely "liking" things.

"Not every moment is a good moment," said Facebook's co-founder and CEO Mark Zuckerberg in a Q&A session at the company's headquarters. He said he realizes people may not want to "like" a current event such as the Syrian refugee crisis or a family member passing away. But he also doesn't want users to merely vote up or down on people's posts.

Ultimately, he said, he hopes to offer users a more expanded way to share their emotional reactions. "It's surprisingly complicated to make an interaction that's that simple," he said.

Another issue Zuckerberg touched on was artificial intelligence, or the ability of machines to think and behave independently. He said AI has the potential to save lives, as in the case of self-driving cars, or to help diagnose and treat disease.

"All new technology has the ability to do good and bad," he said. "I'm fundamentally optimistic about human nature and our ability to do good."