“Japanese roboticist Doctor Masahiro Mori is not exactly a household name—but, for the speculative fiction community at least, he could prove to be an important one. The reason why can be summed up in a simple, strangely elegant phrase that translates into English as “the uncanny valley”.
“Though originally intended to provide an insight into human psychological reaction to robotic design, the concept expressed by this phrase is equally applicable to interactions with nearly any nonhuman entity. Stated simply, the idea is that if one were to plot emotional response against similarity to human appearance and movement, the curve is not a sure, steady upward trend. Instead, there is a peak shortly before one reaches a completely human “look” . . . but then a deep chasm plunges below neutrality into a strongly negative response before rebounding to a second peak where resemblance to humanity is complete.
“This chasm—the uncanny valley of Doctor Mori’s thesis—represents the point at which a person observing the creature or object in question sees something that is nearly human, but just enough off-kilter to seem eerie or disquieting. The first peak, moreover, is where that same individual would see something that is human enough to arouse some empathy, yet at the same time is clearly enough not human to avoid the sense of wrongness. The slope leading up to this first peak is a province of relative emotional detachment—affection, perhaps, but rarely more than that.
“The figure [in the] diagrams this curve of emotional response, plotting it (from top to bottom) first against how closely an entity’s motion resembles human movement, then against physical resemblance to human appearance, and last against a synthesis of the two. It is significant to note, judging from the relative depth of the curves, that Dr. Mori apparently considers motion more important than simple appearance, though he stresses that both are affected at least as much by subtle nuances as by more striking factors.
“The conclusion drawn by the good doctor is that designers of robots or prosthetics should not strive overly hard to duplicate human appearance, lest some seemingly minor flaw drop the hapless android or cyborg into the uncanny valley—a fate to be dreaded by all concerned. He maintains instead that a prosthesis or a robot should be visibly artificial, but smart and stylish in appearance, placing it somewhere near the top of the first peak. This ethos, incidentally, can be seen clearly in a great many science fiction and fantasy manga and animé stories.
“The same factors that inspired Doctor Mori to research and describe the uncanny valley and the rest of the curve to which it belongs are of immediate concern to any creator of fantasy or science fiction. Aside from the readily apparent potential for careful tailoring of a character’s or species’ “look and feel” to evoke a specific reaction from the audience, there are some perhaps surprising possibilities and consequences…”