Reason for plastic monsters – Uncanny valley
There is what’s called the uncanny valley theory. This theory was proposed by Masahiro Mori, a robotics professor at the Tokyo Institute of Technology in the 1970’s on how he envisioned people's reactions to robots that looked and acted almost human. People feel an affinity toward something similar in appearance to them, and the more similar, the more likable. There is higher affinity towards whatever is moving than something staying still. This is why people like pets and children like dolls. What’s interesting is that at some point, when the similarity to a human being increases and becomes quite similar, there’s a moment when this affinity drops dramatically. If you were to plot this relationship on a two-dimensional graph, it’s shaped like a valley where there’s a sharp decline in favorability and thus coined ‘uncanny valley.’ Typically, this phenomenon can be seen in animations or game characters using computer graphics. With the development of computer graphic animations,