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A hypothesized phenomenon holding that humans experience a sense of revulsion or cognitive discomfort when encountering robots, dolls, animations, or other human-like entities that exhibit human characteristics that are not precisely lifelike. The "valley" refers to the portion of the spectrum of realism in which a feeling of the "uncanny" is experienced—i.e. between depictions that are convincingly lifelike and those that are intentionally unrealistic. The concept was first described by Japanese robotics professor Masahiro Mori in 1970. None of our testers reacted positively to that doll. They all found it creepy, which might be indicative of the uncanny valley. The computer-generated faces at the end of the movie really dipped into the uncanny valley—I found them really distracting.
See also: valley