Müller-Lyer illusion


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Müller-Lyer illusion

(ˈmuːləˈlaɪə)
n
(Psychology) an optical illusion in which a line with inward pointing arrowheads is seen as longer than an equal line with outward pointing arrowheads
[C19: named after Franz Müller-Lyer (1857–1916), German sociologist and psychiatrist]