Tech giants divided over digital assistants

Facebook has a team of human "trainers" behind M, who answer some requests that are beyond the capabilities of its artificial intelligence. The company hopes to gather data on users' most frequent requests in order to improve M so it can handle them in the future.

That data is limited, however, as M is so far available only to 10,000 people in the San Francisco Bay area.

Despite M's design, users frequently ask to hear jokes, a request the assistant obliges. Humans tend to anthropomorphise technology, academics say, often looking for a personality or connection even when tech companies intentionally have veered away from such things.

"When you give people this open mic, they will ask anything," said Babak Hodjat, co-founder of AI company Sentient Technologies.

Siri's personality did not change much after Apple acquired the startup in 2010, though she switched from responding in text to speech at the insistence of the late Apple co-founder Steve Jobs, said Adam Cheyer, a co-founder of Siri who is now a vice president at another AI company, Viv Labs.

"He was right on that call," Cheyer said. "The voice is something that people really connect with."

Microsoft interviewed real-life personal assistants to help shape Cortana's personality, said Jonathan Foster, Cortana's editorial manager. The assistant's tone is professional, but she has her whims.

She loves anything science-fiction or math-related - her favourite TV show is "Star Trek" - and jicama is her favorite food because she likes the way it sounds.

Such attention to detail is critical because humans are very particular when it comes to artificial intelligence, said Henry Lieberman, a visiting scientist at the Massachusetts Institute of Technology who studies human-computer interaction.

Companies must be mindful, he said, not to venture into what researchers call  the "uncanny valley", the point at which an artificial intelligence tool falls just short of seeming human. Users become fixated on the small discrepancies, he said.

"It becomes creepy or bizarre, like a monster in a movie that has vaguely human features," Lieberman said.

iDAvatars CEO Norrie J. Daroga said he walked a fine line in creating Sophie, a medical avatar that assesses patients' pain. He gave Sophie a British accent for the US audience, finding users are more critical of assistants that speak like they do.

And she has flaws built in because humans distrust perfection, said Daroga, whose avatar uses technology from IBM's Watson artificial intelligence platform.

Some academics say Siri's personality has been her greatest success: After her release in 2011, users raced to find all her quips. But some of her retorts have caused headaches for Apple.

When asked what to do with a dead body, Siri used to offer joking suggestions such as swamps or reservoirs -- an exchange that surfaced in a 2014 murder trial in Florida.

She is more evasive when asked the question today. "I used to know the answer to this…" she says.

Even in that response, Morgenthaler sees traces of the true Siri.

"It's a little bit of a protest against the corporatisation," he said. "I don't forget, but I've been made to forget."

(Editing by Stephen R. Trousdale and Sue Horton)