Facebook has hired a former IBM executive to be its head of artificial intelligence as it aims to expand its efforts in that area.

The personnel changes come as Amazon, Google and Microsoft also staff up in AI.

Jérôme Pesenti, who led the development of the Watson platform at IBM after IBM acquired a company he co-founded, Vivismimo, is taking the newly created role of vice president of AI, a Facebook spokesman told CNBC in an interview on Tuesday. Most recently Pesenti was at European company BenevolentAI. Quartz originally reported the news.

Meanwhile Yann LeCun, an AI luminary from New York University who joined Facebook in 2013 to be the director the then-new Facebook Artificial Intelligence Research unit, is leaving that post and becoming Facebook's chief AI scientist, the spokesman said.