The secret to making artificial humans that don't creep us meatbags out is in the eyes.
Games have come a long way visually since the days of Pong, but even graphical masterworks like Heavy Rain and Gran Turismo 5 are still obviously artificial. We can't create realistic characters without them being smack-dab in the middle of the Uncanny Valley yet - and a psychological study says that this has everything to do with the eyes.
"There's something fundamentally important about seeing a face and knowing that the lights are on and someone is home," says Dartmouth College's Thalia Wheatley, who co-wrote the study published in Psychological Science with a graduate student, Christine Looser. Whereas humans are inclined to see possible faces everywhere, we recognize that they aren't alive.
The two wanted to determine where exactly the boundary lay between genuine and artificial. To do so, they took a picture of the face of a doll (or a statue), found a similar-looking human, and created a video where one slowly morphed into the other.
When looking at still frames and determining which were human and which were dolls, respondents began to judge the images as "human" about two-thirds of the way through the transformation (that is, closer to the human side of things). A similar experiment found that the defining attribute that caused subjects to view images as lifelike was the eyes - if the eyes didn't look real, the image didn't look real.
It's certainly true when it comes to gaming; how many times have you been otherwise been taken in by a game's graphics only to be jerked out of it thanks to a dull, glassy gaze? Or, in the case of Heavy Rain, Pennsylvanians having vaguely French accents?