As we get closer and closer to something that is unequivocally an artificial intelligence, engineers have tackled another aspect of this; how do you create something that not only acts (and interacts) intelligently, but looks human?
It's a harder question than it appears at first. We're all familiar with depictions of robots from movies and television -- from ones that made no real attempt to mimic the human face in anything more than the most superficial features (such as the robots in I, Robot and the droids in Star Wars) to ones where the producers effectively cheated by having actual human actors simply try to act robotic (the most famous, and in my opinion the best, was Commander Data in Star Trek: The Next Generation). The problem is, we are so attuned to the movement of faces that we can be thrown off, even repulsed, by something so minor that we can't quite put our finger on what exactly is wrong.
This phenomenon was noted a long time ago -- first back in 1970, when roboticist Masahiro Mori coined the name "uncanny valley" to describe the phenomenon. His contention, which has been borne out by research, is that we generally do not have a strong negative reaction to clearly non-human faces (such as teddy bears, the animated characters in most kids' cartoons, and the aforementioned non-human-looking robots). But as you get closer to accurately representing a human face, something fascinating happens. We suddenly start being repelled -- the sense is that the face looks human, but there's something "off." This has been a problem not only in robotics but in CGI; in fact, one of the first and best-known cases of an accidental descent into the uncanny valley was the train conductor in the CGI movie The Polar Express, where a character who was supposed to be friendly and sympathetic ended up scaring the shit out of the kids for no very obvious reason.
As I noted earlier, the difficulty is that we evolved to extract a huge amount of information from extremely subtle movements of the human face. Think of what can be communicated by tiny gestures like a slight lift of a eyebrow or the momentary quirking upward of the corner of the mouth. Mimicking that well enough to look authentic has turned out to be as challenging as the complementary problem of creating AI that can act human in other ways, such as conversation, responses to questions, and the incorporation of emotion, layers of meaning, and humor.
The latest attempt to create a face with human expressivity comes out of Columbia University, and was the subject of a paper in arXiv this week called "Smile Like You Mean It: Animatronic Robotic Face with Learned Models," by Boyuan Chen, Yuhang Hu, Lianfeng Li, Sara Cummings, and Hod Lipson. They call their robot EVA:
The authors write:
Ability to generate intelligent and generalizable facial expressions is essential for building human-like social robots. At present, progress in this field is hindered by the fact that each facial expression needs to be programmed by humans. In order to adapt robot behavior in real time to different situations that arise when interacting with human subjects, robots need to be able to train themselves without requiring human labels, as well as make fast action decisions and generalize the acquired knowledge to diverse and new contexts. We addressed this challenge by designing a physical animatronic robotic face with soft skin and by developing a vision-based self-supervised learning framework for facial mimicry. Our algorithm does not require any knowledge of the robot's kinematic model, camera calibration or predefined expression set. By decomposing the learning process into a generative model and an inverse model, our framework can be trained using a single motor dataset.
Now, let me say up front that I'm extremely impressed by the skill of the roboticists who tackled this project, and I can't even begin to understand how they managed it. But the result falls, in my opinion, into the deepest part of the uncanny valley. Take a look:
The tiny motors that control the movement of EVA's face are amazingly sophisticated, but the expressions they generate are just... off. It's not the blue skin, for what it's worth. It's something about the look in the eyes and the rest of the face being mismatched or out-of-sync. As a result, EVA doesn't appear friendly to me.
To me, EVA looks like she's plotting something, like possibly the subjugation of humanity.
So as amazing as it is that we now have a robot who can mimic human expressions without those expressions being pre-programmed, we have a long way to go before we'll see an authentically human-looking artificial face. It's a bit of a different angle on the Turing test, isn't it? But instead of the interactions having to fool a human judge, here the appearance has to fool one.
And I wonder if that, in the long haul, might turn out to be even harder to do.
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