The simpler the Rorschach spot, the more associations it generates: mathematicians measured the fractal complexity of the famous blots and determined that our brain readily interprets simple patterns, but does not see anything superfluous in complex ones.
The human brain is designed in such a way that it seeks to see meaningful images where there are none. At the beginning of the 20th century, the Swiss Freudian psychoanalyst Hermann Rorschach used this perceptual trait to conduct famous psychological tests in which participants were asked to interpret symmetrical spots.
The value of Rorschach spots for psychoanalysis has since been repeatedly questioned, and in modern techniques the famous pictures are almost never used. However, the ability of the brain to interpret abstract pictures still interests scientists - in particular, mathematicians.
The human brain is designed in such a way that it seeks to see meaningful images where there are none. At the beginning of the 20th century, the Swiss Freudian psychoanalyst Hermann Rorschach used this perceptual trait to conduct famous psychological tests in which participants were asked to interpret symmetrical spots.
The value of Rorschach spots for psychoanalysis has since been repeatedly questioned, and in modern techniques the famous pictures are almost never used. However, the ability of the brain to interpret abstract pictures still interests scientists - in particular, mathematicians.
Rorschach spots are a kind of fractals - self-similar objects, parts of which are similar to larger parts, and those are the whole. The complexity of a fractal can be measured using the indicator D: for a straight line it is equal to one, and the maximum value is two. The closer the value is to one, the simpler the fractal structure is.
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To find out how the complexity of fractals relates to the number of images they generate, scientists took five Rorschach spots used in psychoanalytic sessions in the 1920s and calculated their complexity. Selecting five spots with D from 1.11 to 1.23, the scientists looked at the testimonies of patients who had once been shown these spots and calculated how many different images they saw in each of them.
Romanesco cabbage - an example of a natural fractal object
It turned out that the smaller D, that is, the simpler the fractal structure, the more visual images the image generates. These results surprised the researchers: it was assumed that figures with D from 1.3 to 1.5 would cause more associations, since it is this level of fractal complexity that is most often characteristic of natural fractal objects. The analysis was then repeated using computer-generated blots with a predetermined difficulty (1.05 to 1.95) to ensure that the number of images was not affected by the shades of gray with which the old ink blots were painted. Colored spots were not originally used because color transitions could affect the perception of images on their own, apart from the fractal structure).
Computer generated spots were shown to students. They described every image that they saw in spots, and again the dependence turned out to be direct: the more complex the fractal, the less associations it generates.
In recent years, Rorschach spots have been used to measure creativity. The authors of the study suggest that the pattern they found could be used to refine such tests: so it is possible that more creative people prefer more complex fractals to less complex ones.
The research results are published in the journal PLoS ONE.