Illustration of the Müller-Lyer illusion
The Müller-Lyer Illusion is an optical illusion discovered by Franz Müller-Lyer about 100 years ago. It is about the perception of the length of a line item. A line item that closes with an ordinary arrow point appears shorter than the same line item with inward arrow points.
The perception of this illusion seems to be culture-bound. In cultures without rectangular buildings and objects, people are much less sensitive to this illusion; for example Zulu still living in traditional round huts.
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