Savvy sci-fi fans know better than to trust a human-looking robot. Replicants such as Number Six ("Battlestar Galactica") or Roy Batty ("Blade Runner") have proven treacherous time and time again, especially compared to the likes of lovable old shiny metal C-3PO. But if you didn't know anything about them, your first inclination may be to trust androids that appear human more — based on looks alone.

So says a new study that adds to mounting evidence that humans are superficial and judgmental creatures, quick to draw conclusions about the abilities of robots based heavily on how human the machines look.



At Georgia Tech, two group of adults — 32 men and women between 18 and 23, and 32 between the age of 75 and 85 — were asked to pick the kind of face they'd most prefer on a hypothetical robotic companion. Four of the options included famous androids: Nexi, Kobian, Pearl and Nao. Four were images of regular people, and the last four options were cyborg mashups dreamed up in Photoshop.

In general, graduate student Akanksha Prakash found, older adults favored a human face on their bot whereas millennials had a slight preference for the robots. Nobody liked the hybrids.

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The human likeness was a turnoff for a few of the younger lot (perhaps because they'd seen "Battlestar Galactica" all too recently?). Those who picked robotic faces expected that human-looking machines would be victim to human weaknesses: "Humans lie, but machines don't," is how one subject explained their preference to Prakash.



But when it came to individual tasks, these preferences suddenly shifted.



Across both age brackets, the volunteers made assessments about how "wise or intelligent [the] robots should be," Prakash told NBC News. Machine-like robots were preferred for household chores like cleaning up or vacuuming.

But when it came to decision-making help (advice on where to invest money) or social tasks (helping a person learn a new skill), the respondents selected the human-looking one because it looked smarter, they told Prakash.



Other groups have run similar tests. Take a study published earlier this year, in which groups of volunteers in New Zealand were quizzed about their preferences about how a medical robot should look. Most of them found they could trust a robotic nurse more if the display screen on the bot had a human face. Like Prakash also found, a part-human part-droid cyborg face was the least popular option.

Prakash and Georgia Tech professor of psychology Wendy Rogers are presenting their research at the annual meeting of the Human Factors and Ergonomics Society in San Diego on Wednesday.

It's one thing to imagine a robot you'd want to interact with, and it's quite another to meet one in person. One limitation of such a study, Prakash acknowledged, is that we still don't quite know how we'd react to greeting a human-looking robot in real life because nobody has built one. Yet.

Nidhi Subbaraman writes about technology and science. You can follow her on Facebook, Twitter and Google+.

