Apple's new Siri, the voice-activated virtual assistant built into its new iPhone 4S, has already been hailed as a game changer. Instead of typing commands or moving a mouse or touching a screen, you talk to her. You ask her for things, and she answers in spoken English, soothingly and sometimes amusingly.
She's smart. She's funny. She's -- why is she a she?
Actually, most synthetic computerized voices -- at least in the United States -- are female. Think of the GPS in your car, or the warning voice in the cockpit of a jet. "Pull up! Pull up!" somehow stands out in the testosterone-driven world of flying if a woman says it.
But is that because a higher female voice stands out against the low-frequency roar of an engine? Or is this a terrible case of sexual stereotyping? Would we rather get guidance from a nice, subservient female voice, perhaps the opposite of the bombast we hear from male authority figures?
It may be a mix of biology and learned behavior, said Clifford Nass of Stanford University, who has written extensively about how we relate to machines.
"It's much easier to find a female voice that everyone likes than it is a male voice," he said. "Babies will attend to a female voice more than they will a male one."
And researchers say that apparently begins in the womb, when babies begin to recognize their own mothers' voices. In 2006, Barbara Kisilevsky, a professor at Queens University in Ontario, had pregnant women in Canada and China record poems for their unborn children. When the recordings were played, the fetal heartbeat slowed, a sign that the effect was soothing. When anyone else read the poem, the fetal heartbeat sped up.
There's history at work too, said Tim Bajarin of Creative Strategies, Inc., which follows Apple closely. "When phones became popular, we had these things known as switchboards, and they were run by women. AT&T was known as 'Ma Bell.'"
Apple, Nass said, is trying to position itself in the U.S. as likable and accessible. "They don't boast the fastest or most powerful machines, they're the nicest and easiest to use.
"A male voice is seen as a better teacher of technology," he said, "and a female voice is better for everything else.
"So for Apple, it's a matter of expertise versus caring. It's forever a tradeoff in technology."
Of course, cultural preferences vary from country to country. In France and the U.K., Siri is a guy. Why? Apple is silent on the matter. It did not return our messages.
Nass writes that a decade ago BMW installed female voices in cars in Germany -- but men there complained, refusing to take directions from a woman.
Then there's the HAL factor, as in the HAL 9000 computer from Stanley Kubrick's "2001: A Space Odyssey." HAL tried to kill off his human crewmates -- and he did it in the dispassionate voice of actor Douglas Rain: "Dave. My mind is going. I can feel it."
"That voice is burned into our collective psyche," said Bajarin. "Hal is sinister."
"Siri, I love you," sings the musician Jonathan Mann in a howlingly funny video duet with his iPhone.
"You say that to all the virtual assistants," answers Siri.
Of course, everyone may be overthinking this. Bajarin, chortling, said his assistant had the best line of the day:
"I wouldn't want to take directions from a male, because males are always getting lost."