Why is the mere image of a zombie so universally repulsive?  A theory in the field of robotics and computer animation called the Uncanny Valley may have the answer.

The Uncanny Valley holds that as artificial representations of humans become more realistic they are also more appealing, but only to a point.  When a facsimile looks and acts too much like an actual human it repels viewers.  Applied to zombies, the disconnect between our intellectual understanding that the the undead aren’t people anymore and our emotional urge to see them as somehow still human is at the root of our repulsion.

The graph below illustrates the sharp drop in positive human reaction in the Uncanny Valley, with zombies causing the strongest negative response.


  1. Another thing about Uncanny Valley: as a rule, humans have a preference for symmetry. The more symmetrical a face is, the more appealing we find it. However, human faces are noted by the imperfections. So, once a robot face reaches a certain point of looking human, our brain is able to pick up that something is off about it (that it is too symmetrical), and therefore we find it repulsive. Zombies are the exact reverse of this. Their faces are human, but they are far from symmetrical. Rot, environmental factors and injuries cause their faces to lose any symmetry they had in life, which causes our mind to pick up that though they look human on the most basic level, something is off.

  2. re: the graph
    i think ‘uncanny valley’ looks rather spiffing with a moustache :{D

  3. This also explains why bad computer animation can be so unpleasant. Flawless animation is good and lousy animation on the other side of the valley can work fine. It’s the computer animation that just misses depicting a human, with eyes and facial expressions somehow off, that are like fingernails on a chalkboard.

  4. really because they are dead and and are alive. are you saying a dead person walking around eating people with blood and body parts missing not SCARY!!!

  5. At the risk of getting overly philosophical, you might say that reaction is based upon a zombie/robots lack of soul or, for the sake of the atheists in the world, human-ness. If something seems totally unlike a human, we don’t subconsciously look for it to act like a person. The more it looks like us, the more we expect it to act like it us. If it doesn’t, it starts to feel wrong to whatever it is that makes us people. It lacks intrinsic human traits. Too close for comfort may describe it best.

    It would suck if zombies had no traits which would distinguish it from a living person. It would make quick decision making (destroy it, run away from it, or talk to it) very difficult. If I have to deal with zombies, the ones that are most assuredly dead would be the easiest to make choices about. If it’s groaning, reaching towards me and gnashing its teeth, I know it’s either a zombie or a politician. Either way, I know the morally proper thing to do is to destroy its brain with a blunt or bladed weapon.

    Thanks for the thought provoking article. I’ll look into this phenomenon. As Sun Tzu said, know your enemy and know yourself.

    • It’s not about the actual presence of souls (if they exist at all), but about the illusion of the presence of a soul.

      Though really, the uncanny valley thing is likely an instinct developed to keep you healthy (lots of sicknesses tend to push people down closer to the valley) and to keep you from having sick offspring (if you don’t hang around people with genetic defects (that make them look repulsive) the smaller the odds of you mating with them and having sick kids)

      • That’s a good theory. I can totally see the validity of it being an evolutionary mechanism to keep the gene-pool clean. Respect.

        I’m on the fence about souls. While I believe there is something going on that keeps the world running the way it does, I don’t have an attachment to it being a god-thing or simply the way the Universe works. Intuitively, I believe in Natural Law and admit total ignorance of anything beyond. If a label had to be slapped on me, I reckon I’d refer to myself as agnostic.

        As far as zombies are concerned, I’m more interested in destroying them as quickly as possible, whether they look humanish or not. As ayanti pointed out, “a dead person walking around eating people” is disturbing enough without dithering about how human they are. It’s still great fun to discuss.

        Thanks for sharing your thoughts @TiagoTiago, @ayanti, and @Mark.

      • You ever seen the video of the hairless chimp walking upright? It’s as you say “disturbing” but you can’t figure out why at first. Then the “too human” thing hits you.

  6. ? Cuz they’re zombies, and it’s just the way it is?

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