- Vincent Ro

- May 9, 2025
- 3 min read
Look at her again. The girl from The Polar Express, Holly, is smiling at someone off-camera. Her cheeks are flushed. Her hair catches the light. Every freckle is in place. And yet your stomach has already done the thing it does, that small involuntary pull-back, the sense that you are looking at something that should not be looking back. You can’t quite name what's wrong. The eyes, maybe, or the way the smile sits a half-second too long. Something. That something has a name; the Uncanny Valley was originally developed in 1970 by Japanese robotics engineer Masahiro Mori.¹ At face value, this phenomenon might just seem like an instinct you have and nothing more, but there is a lot more going on beneath the surface.
The process of analyzing human faces and emotions is complex, involving a network of brain regions like the fusiform face area (FFA) and the amygdala, working together to interpret facial expressions and extract meaning for social interaction.² The specific patterns of facial muscle activity that create emotional expressions have been shaped over millions of years of evolution, and three main ideas attempt to explain why slight deviations from them set off such a strong internal alarm.³
The first is the evolutionary theory, which suggests there was a point in our history where survival depended on detecting subtle deviations from healthy human features. A face that looked almost right, but not quite, could signal disease, genetic abnormalities, or even a corpse. Discomfort, in other words, was useful. The same instinct that makes Holly unsettling once helped our ancestors avoid people and things that might kill them. ⁴
The second is cognitive dissonance, defined as the mental discomfort felt when people hold attitudes or beliefs that conflict with one another; or, in this case, when perception conflicts with expectation.⁵ When something looks human, we subconsciously expect it to behave humanely. So when that expectation isn’t met, either through a blink that comes a second too late or a smile that holds a second too long, the mismatch creates a low, persistent unease. Our brain rings the alarm before we recognize it.⁶
The third is impaired empathy, the inability to fully understand or share the feelings of another. Small cues like micro-expressions, eye contact, and body language form the foundation of human connection.⁷ When those boxes are left unchecked, our capacity to empathize short circuits. The figure in front of us looks like a person, but we can’t connect with it as one. That gap is where the feeling of eeriness comes from.⁸
The more we interact with “almost-humans,” the more we might have to ask what, exactly, we were responding to all along–the face or the individual behind it.
The Uncanny Valley is not just a feeling you get in your gut when you look at something off, it’s the product of deeply rooted psychological and evolutionary mechanisms. Our brains have spent millions of years learning to recognize human faces and to ring an internal alarm when something looks human but doesn’t feel quite right. From unnatural movements to abnormal reactions, these glitches disrupt our set of expectations, and discomfort quickly follows. As AI and hyper-realistic technology become a growing part of our daily lives, this valley matters more than ever. With growing exposure to these almost-human entities (CGI characters, deepfakes, social robots), the line between human and machine starts to blur.⁹ The more we interact with “almost-humans,” the more we might have to ask what, exactly, we were responding to all along–the face or the individual behind it.
Masahiro Mori, "The Uncanny Valley," IEEE Spectrum 49, no. 6 (2012): 98–100. Originally published 1970.
Nancy Kanwisher et al., “The Fusiform Face Area,” Journal of Neuroscience, 1997; Ralph Adolphs, “Recognizing Emotion from Facial Expressions,” Behavioral and Cognitive Neuroscience Reviews, 2002.
Paul Ekman, "Facial Expression and Emotion," American Psychologist 48, no. 4 (1993): 384–392.
Mahdi M. Moosa and S. M. Minhaz Ud-Dean, “Danger Avoidance,” Biological Theory, 2010.
Leon Festinger, A Theory of Cognitive Dissonance (Stanford: Stanford University Press, 1957).
Ayse Pinar Saygin et al., “Predictive Coding and the Uncanny Valley,” Social Cognitive and Affective Neuroscience, 2012.
Paul Ekman and Wallace V. Friesen, "Constants Across Cultures in the Face and Emotion," Journal of Personality and Social Psychology 17, no. 2 (1971): 124–129.
Angela Tinwell et al., "Perception of Psychopathy and the Uncanny Valley in Virtual Characters," Computers in Human Behavior 29, no. 4 (2013): 1617–1625.
Karl F. MacDorman and Hiroshi Ishiguro, "The Uncanny Advantage of Using Androids in Cognitive and Social Science Research," Interaction Studies 7, no. 3 (2006): 297–337.





