The bouba/kiki effect is a non-arbitrary mapping between speech sounds and the visual shape of objects. It was first documented by Wolfgang Köhler in 1929 using nonsense words. The effect has been observed in American university students, Tamil speakers in India, young children, and infants, and has also been shown to occur with familiar names. It is absent in individuals who are congenitally blind. The effect was investigated using fMRI in 2018. The bouba/kiki effect is one form of sound symbolism. Research Discovery This effect was first observed by Georgian psychologist Dimitri Uznadze in a 1924 paper. He conducted an experiment with 10 participants who were given a list with nonsense words, shown 6 drawings for 5 seconds each, then had to pick a name for the drawing from the list of given words. He describes the different "strategies" participants developed to match words to drawings and quotes their reasoning. He also describes situations where participants described very specific forms that they associated with a nonsense word, without reference to the shown drawings. He develops a theory of four factors that influence the way names for objects are decided. In total there were 42 words. For one particular drawing, 45% picked the same word. For three others, the percentages were 40%. Uznadze points out that this is significantly more overlap than one could expect, given the high number of possible words. He speculates that there must therefore be certain regularities "which the human soul follows in the process of name-giving". German American psychologist Wolfgang Köhler referred to Uznadze's experiment in a 1929 book which showed 2 forms and asked readers which shape was called "takete" and which was called "maluma". Although not explicitly stated, Köhler implies that there is a strong preference to pair the jagged shape with "takete" and the rounded shape with "maluma". Extension to other contexts In 2001, V. S. Ramachandran and Edward Hubbard repeated Köhler's experiment using the words "kiki" and "bouba" and asked American college undergraduates and Tamil speakers in India, "Which of these shapes is bouba and which is kiki?" In both groups, 95% to 98% selected the curvy shape as "bouba" and the jagged one as "kiki", suggesting that the human brain somehow attaches abstract meanings to the shapes and sounds consistently. Daphne Maurer and colleagues showed that even children as young as 2 years old may show this preference. More recent work