Uncanny valley

The uncanny valley is a hypothesis in the field of robotics^[1] and 3D computer animation,^[2][3] which holds that when human replicas look and act almost, but not perfectly, like actual human beings, it causes a response of revulsion among human observers. The "valley" in question is a dip in a proposed graph of the positivity of human reaction as a function of a robot's human likeness.

The term was coined by the robotics professor Masahiro Mori as Bukimi no Tani Genshō (不気味の谷現象) in 1970. The hypothesis has been linked to Ernst Jentsch's concept of "the uncanny" identified in a 1906 essay, "On the Psychology of the Uncanny."^[4][5][6] Jentsch's conception was elaborated by Sigmund Freud in a 1919 essay entitled "The Uncanny" ("Das Unheimliche").^[7]

Hypothesis

Mori's original hypothesis states that as the appearance of a robot is made more human, a human observer's emotional response to the robot will become increasingly positive and empathic, until a point is reached beyond which the response quickly becomes that of strong revulsion. However, as the robot's appearance continues to become less distinguishable from that of a human being, the emotional response becomes positive once more and approaches human-to-human empathy levels.^[8]

This area of repulsive response aroused by a robot with appearance and motion between a "barely human" and "fully human" entity is called the uncanny valley. The name captures the idea that an almost human-looking robot will seem overly "strange" to a human being, will produce a feeling of uncanniness, and will thus fail to evoke the empathic response required for productive human-robot interaction.^[8]

Hypothetical basis

A number of hypotheses have been proposed to explain the cognitive mechanism underlying the phenomenon:

• Mate selection. Automatic, stimulus-driven appraisals of uncanny stimuli elicit aversion by activating an evolved cognitive mechanism for the avoidance of selecting mates with low fertility, poor hormonal health, or ineffective immune systems based on visible features of the face and body that are predictive of those traits.^[10][11]
• Mortality salience. Viewing an "uncanny" robot elicits an innate fear of death and culturally-supported defenses for coping with death’s inevitability.... [P]artially disassembled androids... play on subconscious fears of reduction, replacement, and annihilation: (1) A mechanism with a human facade and a mechanical interior plays on our subconscious fear that we are all just soulless machines. (2) Androids in various states of mutilation, decapitation, or disassembly are reminiscent of a battlefield after a conflict and, as such, serve as a reminder of our mortality. (3) Since most androids are copies of actual people, they are doppelgängers and may elicit a fear of being replaced, on the job, in a relationship, and so on. (4) The jerkiness of an android’s movements could be unsettling because it elicits a fear of losing bodily control."^[12]
• Pathogen avoidance. Uncanny stimuli may activate a cognitive mechanism that originally evolved to motivate the avoidance of potential sources of pathogens by eliciting a disgust response. “The more human an organism looks, the stronger the aversion to its defects, because (1) defects indicate disease, (2) more human-looking organisms are more closely related to human beings genetically, and (3) the probability of contracting disease-causing bacteria, viruses, and other parasites increases with genetic similarity.”^[11][13] Thus, the visual anomalies of android robots and animated human characters have the same effect as those of corpses and visibly diseased individuals: the elicitation of alarm and revulsion.
• Sorites paradoxes. Stimuli with human and nonhuman traits undermine our sense of human identity by linking qualitatively different categories, human and nonhuman, by a quantitative metric, degree of human likeness.^[14]
• Violation of human norms. The uncanny valley may "be symptomatic of entities that elicit a model of a human other but do not measure up to it."^[15] If an entity looks sufficiently nonhuman, its human characteristics will be noticeable, generating empathy. However, if the entity looks almost human, it will elicit our model of a human other and its detailed normative expectations. The nonhuman characteristics will be noticeable, giving the human viewer a sense of strangeness. In other words, a robot stuck inside the uncanny valley is no longer being judged by the standards of a robot doing a passable job at pretending to be human, but is instead being judged by the standards of a human doing a terrible job at acting like a normal person. This has been linked to perceptual uncertainty and the theory of predictive coding ^[16].
• Religious constructions of human identity. The existence of artificial but humanlike entities is viewed by some as a threat to the concept of human identity, as constructed in the West and the Middle East. This is particularly the case with the Abrahamic religions (Christianity, Islam, and Judaism), which emphasize human uniqueness.^[17] An example can be found in the theoretical framework of psychiatrist Irvin Yalom. Yalom explains that humans construct psychological defenses in order to avoid existential anxiety stemming from death. One of these defenses is "specialness", the irrational belief that aging and death as central premises of life apply to all others but oneself.^[18] The experience of the very humanlike "living" robot can be so rich and compelling that it challenges humans' notions of "specialness" and existential defenses, eliciting existential anxiety.

Research

Research into the evolutionary mechanism behind the aversion associated with the uncanny valley was examined with one 2009 study. A group of five monkeys were shown three images: two different 3D monkey faces (realistic, unrealistic), and a real photo of a monkey's face. The monkeys' eye-gaze was used as a proxy for preference or aversion. Since the realistic 3D monkey face was looked at less than either the real photo, or the unrealistic 3D monkey face, this was interpreted as an indication that the monkey participants found the realistic 3D face aversive, or otherwise preferred the other two images. As one would expect with the uncanny valley, more realism can lead to less positive reactions, and this study demonstrated that neither human-specific cognitive processes, nor human culture explain the uncanny valley. In other words, this aversive reaction to realism can be said to be evolutionary in origin.^[19]

As of 2011, researchers at University of California San Diego (UCSD) and California Institute for Telecommunications and Information Technology (Calit2) are testing human brain activations related to the uncanny valley.^{[20] [21]}. In an fMRI study, a group of cognitive scientists and roboticists found the biggest differences in brain responses for uncanny robots in parietal cortex, on both sides of the brain, specifically in the areas that connect the part of the brain’s visual cortex that processes bodily movements with the section of the motor cortex thought to contain mirror neurons (neurons also known as “monkey-see, monkey-do neurons”). The researchers say they saw, in essence, evidence of mismatch or perceptual conflict.^[22] The brain “lit up” when the human-like appearance of the android and its robotic motion “didn’t compute.” Saygin, a professor from UCSD said “The brain doesn’t seem tuned to care about either biological appearance or biological motion per se,” said Saygin, an assistant professor of cognitive science at UC San Diego and alumna of the same department. “What it seems to be doing is looking for its expectations to be met – for appearance and motion to be congruent.” ^{[23] [24] [25]}

Viewer perception of facial expression and speech and the Uncanny Valley in realistic, human-like characters intended for 3D immersive environments and video games is also being investigated by Tinwell et al., 2011.^[26] Building on the body of work already undertaken in android science, this research intends to build a conceptual framework of the Uncanny Valley using 3D characters generated in a real-time gaming engine analysing how cross modal factors of facial expression, and speech may exaggerate the uncanny.

Design principles

A number of design principles have been proposed for avoiding the uncanny valley:

• Design elements should match in human realism. A robot may look uncanny when human and nonhuman elements are mixed.^[27] For example, both a robot with a human voice or a human being with a synthetic voice have been found to be eerier than a robot with a synthetic voice or a human being with a human voice.^[5] For a robot to give a more positive impression, its degree of human realism in appearance should also match its degree of human realism in behavior.^[28] If an animated character looks more human than its movement, this gives a negative impression.^[29] Human neuroimaging studies also indicate matching appearance and motion kinematics are important.^[30][31]
• Reducing conflict and uncertainty by matching appearance, behaviour and ability In terms of performance, if a robot looks too appliance-like, people will expect little from it; if it looks too human, people will expect too much from it.^[28] A highly human-like appearance leads to an expectation that certain behaviors will be present, such as humanlike motion dynamics. This likely operates at a sub-conscious level and may have a biological basis. Neuroscientists have noted "when the brain's expectations are not met, the brain.. generates a "prediction error"... As human-like artificial agents become more commonplace, perhaps our perceptual systems will be re-tuned to accommodate these new social partners. Or perhaps, we will decide it is not a good idea to make [robots] so clearly in our image after all."^{[31] [32]}
• Human facial proportions and photorealistic texture should only be used together. A photorealistic human texture demands human facial proportions, or the computer generated character can fall into the uncanny valley. Abnormal facial proportions, including those typically used by artists to enhance attractiveness (e.g., larger eyes), can look eerie with a photorealistic human texture. Avoiding a photorealistic texture can permit more leeway.^[33]

Criticism

A number of criticisms have been raised concerning whether the uncanny valley exists as a unified phenomenon amenable to scientific scrutiny:

• Good design can lift human-looking entities out of the valley. David Hanson has criticized Mori's hypothesis that entities approaching human appearance will necessarily be evaluated negatively.^[34] He has shown that the uncanny valley that Karl MacDorman and Hiroshi Ishiguro^[35] generated – by having participants rate photographs that morphed from humanoid robots to android robots to human beings – could be flattened out by adding neotenous, cartoonish features to the entities that had formerly fallen into the valley.^[34]
• The uncanny appears at any degree of human likeness. Hanson has also pointed out that uncanny entities may appear anywhere in a spectrum ranging from the abstract (e.g., MIT's robot Lazlo) to the perfectly human (e.g., cosmetically atypical people).^[34] Capgras syndrome is a relatively rare condition in which the sufferer believes that people (or, in some cases, things) have been replaced with duplicates. These duplicates are rationally accepted to be identical in physical properties, but the irrational belief is held that the "true" entity has been replaced with something else. Some sufferers of Capgras syndrome claim that the duplicate is a robot. Ellis and Lewis argue that the syndrome arises from an intact system for overt recognition coupled with a damaged system for covert recognition, which leads to conflict over an individual being identifiable but not familiar in any emotional sense.^[36] This supports the view that the uncanny valley could arise due to issues of categorical perception that are particular to the manner in which the social brain processes information.^[31][37]
• The uncanny valley is a heterogeneous group of phenomena. Phenomena labeled as being in the uncanny valley can be diverse, involve different sense modalities, and have multiple, possibly overlapping causes, which can range from evolved or learned circuits for early face perception^[33][38] to culturally-shared psychological constructs.^[39] People's cultural backgrounds may have a considerable influence on how androids are perceived with respect to the uncanny valley.^[40]

Similar effects

An effect similar to the uncanny valley was noted by Charles Darwin in 1839:

The expression of this [Trigonocephalus] snake’s face was hideous and fierce; the pupil consisted of a vertical slit in a mottled and coppery iris; the jaws were broad at the base, and the nose terminated in a triangular projection. I do not think I ever saw anything more ugly, excepting, perhaps, some of the vampire bats. I imagine this repulsive aspect originates from the features being placed in positions, with respect to each other, somewhat proportional to the human face; and thus we obtain a scale of hideousness.

—Charles Darwin, The Voyage of the Beagle^[41]

A similar "uncanny valley" effect could, according to the ethical-futurist writer Jamais Cascio, show up when humans begin modifying themselves with transhuman enhancements (cf. body modification), which aim to improve the abilities of the human body beyond what would normally be possible, be it eyesight, muscle strength, or cognition.^[42] So long as these enhancements remain within a perceived norm of human behavior, a negative reaction is unlikely, but once individuals supplant normal human variety, revulsion can be expected. However, according to this theory, once such technologies gain further distance from human norms, "transhuman" individuals would cease to be judged on human levels and instead be regarded as separate entities altogether (this point is what has been dubbed "posthuman"), and it is here that acceptance would rise once again out of the uncanny valley.^[42] Another example comes from "pageant retouching" photos, especially of children, which some^[43] find disturbingly doll-like.

Film and television

Roboticist Dario Floreano notes that the concept of the uncanny valley is taken seriously by the film industry due to the negative audience reactions to the animated baby in Pixar's 1988 short film Tin Toy.^[44][45]

In the 2008 30 Rock episode "Succession", Frank Rossitano explains the uncanny valley concept, using a graph and Star Wars examples, to try to convince Tracy Jordan that his dream of creating a pornographic video game is impossible. He also references the computer animated film The Polar Express.^[46]

In the Doctor Who serial The Robots of Death (1977), a similar concept is referred to as "Grimwade's Syndrome" which is described as a psychological condition among people with frequent contact with robots, attributed to the robots moving like humans, but without any of the characteristic human body language. In the mind of those afflicted, they appear to be, in the words of the Doctor, "surrounded by walking, talking dead men."

Episode 12 (season 5) of Criminal Minds (2010) is titled "The Uncanny Valley" and explores the theme through the lens of a serial abductress (and murderess) who chemically paralyzes the women she abducts and treats them like dolls.

In the season 6 episode of Red Dwarf, "Out of Time" (1993), Kryten alludes to the uncanny valley as the reason his faceted head was designed to look so inhuman. The series of Mechanoids that preceded his were hyper-realistic, and people's natural revulsion to such realistic-appearing machines severely hurt their sales.

The 1972 satirical thriller The Stepford Wives and its 1975 and 2004 movie adaptations implicitly feature the concept of the uncanny valley. After the story's protagonist moves to a suburban residence, she notices increasingly uncharacteristic behavior by the other women in her community. As they become more docile, wholly subjecting their behavior and ambitions to the needs of their male partners, she begins to suspect a conspiracy where the human females are being replaced by gynoids.

In the 2010 film The Last Airbender, Appa the flying bison, which is a CGI character based on a character of the same name in the television series, Avatar: The Last Airbender, has been called "uncanny."Geekosystem's Susana Polo found the CGI version of Appa "really quite creepy," noting "that prey animals (like bison) have eyes on the sides of their heads, and so moving them to the front without changing rest of the facial structure tips us right into the Uncanny Valley."

In reviewing The Polar Express in 2004, CNN.com reviewer Paul Clinton references his uncanny valley response directly: "Those human characters in the film come across as downright... well, creepy. So The Polar Express is at best disconcerting, and at worst, a wee bit horrifying."^[47]

See also

Notes

References

External links

• The Uncanny Valley: Animations that give us the creeps CBC Radio interview with Lawrence Weschler, author of Uncanny Valley: Adventures in the Narrative.
• IEEE Spectrum article "Who's Afraid of the Uncanny Valley," April 2, 2010 A compilation of images of humanoid robots, lifelike mannequins and CGI humans, and a discussion of origins and scientific foundations of the uncanny valley hypothesis.
• Your Brain on Androids UCSD news release about human brain and the uncanny valley.
• On The Media Transcript and audio archive of their story, "The Uncanny Valley", March 5, 2010.
• IEEE-RAS Humanoids-2005 Workshop: Views on the Uncanny Valley. Was held in Tsukuba, Japan, near Tokyo on December 5, 2005.
• The Uncanny Valley (Dave Bryant)
• Almost too human and lifelike for comfort - research journal for an uncanny valley PhD project
• Relation between motion and appearance is communication between androids and humans
• Android Science video, the Discovery Channel, 24 March 2005, discusses android science, the uncanny valley and features an Actroid.
• Wired article: "Why is this man smiling?", June 2002.
• The Polar Express: A Virtual Train Wreck, Part 1 - Animation Director Ward Jenkins discusses in length about the use of motion capture in the film. In Part 2, he tries to "fix" the uncanny valley problem by using Photoshop to tweak some of the characters in the film.
• This robotic mouth, apparently designed to help hearing-impaired people learn to enunciate vowels correctly, is an example of the uncanny valley
• The Uncanny Valley (in On The Media)
• Androids Are the Future: Scenes From Vanguard, even more disturbing than Repliee. (Not available in the UK)
• The Uncanny valley- a visual explanation of the hypothesis with the application in gaming.