If when observing a robot with an almost human appearance you experience a series of unpleasant sensations, it is possible that you are under a phenomenon explained by the Restless Valley Theory .

This theory tries to give an explanation to the reactions that a person lives in the presence of an excessively human figure or image, but that on the other hand is not enough .

What is Restless Valley Theory?

The Theory of Restless Valley, as well as the term Restless Valley itself, are concepts related to the world of robotics and 3D animation that refer to a curve of the reaction of people to the presence of an anthropomorphic figure. That is, in the presence of a non-living figure or object, but with a great appearance of a person. These anthropomorphic figures can refer to android robots or to highly realistic 3D animations.

The term “Restless Valley” was created by professor and robotics specialist Masahiro Mori in 1970, and its Japanese name was Bukimi no Tani Gensho. Under the translation known as Restless Valley, there is a metaphor that tries to clarify the reactions that people experience in the presence of a robot in human form.

According to this theory, a person’s reaction to an anthropomorphic robot is increasingly positive and empathetic as the figure’s appearance becomes more and more human. However, there is a turning point where this reaction changes completely; becoming an aversion response due to the excess of similarity .

The name “valley” refers to the slope of the curve in the graph prepared by Mori, which calculates how favorable the human response is to the presence of an anthropomorphic figure: it rises as its human appearance also grows, until it reaches a point where the first falls when the second is very high.

On the other hand, the term “disturbing” refers to the feeling of strangeness or aversion caused by the perception of something that seems human but is not really so.

What causes this aversion?

Although it has not yet been possible to reach a completely valid conclusion about the causes of this sensation, there are various theories that try to explain why this phenomenon occurs.

1. Hypothesis of disease rejection

A hypothesis developed by psychologist Thalia Wheatley indicates that, after centuries of evolution, we humans have developed the ability to detect any kind of distortion in other humans and identify it or associate it with any kind of physical or mental illness .

Therefore, the feeling of aversion to something that seems human, but shows clear signs that it is not, would be nothing more than a natural defence of our brain against the idea of illness and even death.

This means that all those distortions or oddnesses that we perceive before an anthropomorphic figure are directly associated, by our brain, to the idea or image of people considerably ill or even dead, thus originating an aversion or disgust response.

2. The Sorites Paradox

Also known as the paradox of the heap. Although this explanation is not directly related to the Restless Valley Theory, many experts and theorists have used it to try to find the cause of it.

This paradox manifests itself when a person tries to use common sense about a vague, imprecise or unclear concept. In the case of the Uneasy Valley, the human-looking figures end up undermining our sense of identity by trying to find a logical explanation for what we are observing. This generates a negative feeling and rejection of what we do not understand.

3. Hypothesis of the violation of human norms

According to this hypothesis, if a figure or robot has an appearance that could be identified with the human one, it generates a certain degree of empathy. However, when this figure only partially resembles a human, possessing remarkable non-human characteristics (such as a lack of clear expression of feelings or unnatural body movements) generating a feeling of uncertainty and a reaction of repulsion .

4. Hypothesis of the religious definition of person

In societies that are strongly influenced by religious standards and concepts about the human being , the existence of artificial and anthropomorphic objects or figures poses a threat to the idea of the human being as conceived by different religions.

5. Hypothesis of “specialism”

The American psychiatrist Irvin Yalom explains that human beings, faced with the fear of death, create a series of psychological defenses that curb the anxiety caused by the certainty that one day we will die. One of these defenses is “specialism”. This is an irrational and unconscious belief by which we assume that death is something inherent in life but that it is something that only applies to others, not to ourselves.

Therefore, the confrontation to an object or robot with a high human countenance can become so intense that it causes a discrepancy between “specialism” and existential defenses, generating a sensation of vital anguish.

Reviews of Mori’s model

As with most unscientific theories, the Restless Valley Theory has not escaped criticism. Some of the experts in the world of robotics reject Mori’s idea on the grounds that there is no basis for the reaction curve he created.

Furthermore, they rely on the fact that at the moment it is only possible to create partially human-like robots , so the theory would not have sufficient foundation.
Instead, they claim that in any case a kind of cognitive dissonance could be generated by which our brain generates some expectations about how a human should be, expectations that with this type of humanoid figures would not be covered.