(Story refiles to clarify in eighth paragraph that software refers to artificial intelligence technology)

By Joshua Franklin

ZURICH (Reuters) - UBS, the world's biggest wealth manager, is looking at using artificial intelligence to help clients decide how to invest their money by watching their facial expressions.

The Swiss bank is running several pilot programs to see how it can get the best out of artificial intelligence (AI) technology, said UBS Chief Investment Officer Mark Haefele, who oversees around $2 trillion in assets.

One tool examines and interprets subtle facial expressions made by clients while they watch a video about financial planning.

"This helps uncover biases," Haefele said in an interview. "You can say, 'Look, you said your biggest interest is planning for the long term but this artificial intelligence is showing us what you're really excited about are short-term trading ideas.'"

The program is now being tested and UBS is still considering whether to roll it out across the bank.

Haefele believes it could speed up the process of finding out what millionaires and billionaires want.

"Everyone has less time so one of the goals is to help clients ask better questions and then get the right investment opportunities," he said.

UBS is also exploring the use of artificial intelligence software to help judge applicants on traits - such as teamwork, curiosity and determination.

Wealth managers are turning to a range of automated technologies to try to win business and better advise clients.

A survey released on Tuesday by Investopedia showed financial advisers in the United States are increasingly incorporating so-called 'robo-advisory' services – automated, algorithm based wealth management advice – into their practices.

(Editing by Mark Potter)