How the Uncanny Valley Works

Studies on the Uncanny Valley
An Actroid smiles blankly. Eyes are hard to replicate, and therefore contribute to the uncanny valley effect in human replicas. Andia/UIG via Getty Images

A concern in studying the uncanny valley effect is that it's tough to quantify affinity and lifelikeness. But researchers have conducted experiments to detect and parse the uncanny valley effect, and even attempt to provide mathematical explanations for it. One key finding is that the uncanny valley does not appear in every study that looks for it, and when it does appear, it does not always do so with equal intensity. This suggests that the effect does exist, but is caused by specific factors and therefore doesn't show up in studies that don't include those factors. For instance, one study found that people are better able to discern real from artificial humans when they're looking only at eyes (as compared to looking at just a nose or a mouth), indicating that getting the eyes right is an important step in creating realistic human replicas [source: Looser & Wheatley].

Something as simple as an unnatural pose or expression on an android's face might invoke the uncanny valley effect, as demonstrated in research that showed people were most disturbed by humanlike virtual characters who did not display adequate facial responses when startled [source: Tinwell et al]. Replicas also dip farther into the uncanny valley when they try to "deceive" the viewer into thinking they're human rather than simply portraying very realistic androids. A 2012 study revealed that people are the most creeped out when humanlike robots seem like they have minds and the ability to feel and sense [source: Gray and Wegner]. And one study discovered that the uncanny valley effect only occurs when people are looking at faces that are familiar to their ethnic group [source: Hsu].

The phenomenon extends beyond people — another fascinating experiment measured the responses of monkeys to a range of real and unrealistic and realistic artificial monkey faces. The researchers found that the monkeys experienced a clear valley when viewing the realistic artificial faces [source: Steckenfinger and Ghazanfar]. Taken together, the research suggests that the uncanny valley does exist, but that it elicits many human responses. That means that overcoming the uncanny valley would be a difficult task, and an artificial human that transcends the uncanny valley for some viewers may not do so for others.

Mori's theory on conquering the valley? Don't even try. He suggested roboticists keep their androids on the left side of the valley, using exaggerated features to increase affinity and avoid the uncertainty and creepiness a more realistic android might exude (like the Disney strategy). Other researchers suggest that it is impossible to get through the valley because it is actually a wall — humans' ability to detect subtle differences in human replicas increases alongside technological gains that make artificial humans more realistic [source: Tinwell].

There are uncanny valley examples outside of academia, though. What are some familiar figures that live in the uncanny valley? Let's find out.

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