And to all that they added animation modules, giving a body—well, a "body"—to their program. Ellie was born.

If you have a conversation with Ellie, her creators say, she will be able to suss out symptoms of anxiety, depression, and—of particular interest to DARPA—PTSD. The avatar can also, they say, help to prepare soldiers before they've gone to the battlefield. "You want to train people on non-verbal behaviors," Morency puts it; so, for example, soldiers can be attuned to subtle facial cues from people they might encounter in a theater of war.

Morency and his team have been demonstrating Ellie and her fellow virtual-psychologists in Los Angeles, to people curious about what it's like to be analyzed by an avatar. So far, more than 500 people have talked to her. And—here's the surprising thing—they seem to enjoy the experience. The set time for each demo was initially 15 minutes; Morency says people kept extending their time with Ellie, however—up to 30 minutes. That's because, Morency figures, "they don't feel judged" by her.

And that's in turn because, as he puts it,

Ellie is an interviewer, but she is there as a computer. She doesn't have judgment directly. So people love talking to her.... they're more themselves. They're really expressing and showing something that usually if you know that people are around you—or as an interviewer—they think, 'Oh, I'm going to be careful.' But with Ellie, they're more themselves.

Morency compares the appeal, actually, to that of pets. "People, after talking to Ellie, they feel better," he points out. "Some people talk to their dogs; even though the dogs don't understand it... I think there's a little bit of that effect—just talking with someone makes you feel better."

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