Nearly a century after Hermann Rorschach invented his ink blot test, a controversial assessment that he used in psychiatric clinics. Patients gave many different interpretations of the shapes and figures in Rorschach’s blots.
Now, in the journal Plos One, R. Taylor et al at the University of Oregon, claim to have an answer. They analysed ten Rorschach ink blots and found that the five black and white patterns varied in their fractal complexity. The less complex the fractals in the blots, the more images people tended to see.
Rorschach’s Blot Seven is shown at the top (a). Note the tell-tale fractal signatures of irregular curves or shapes at the edges of the symmetrical image. Some people see a woman’s head with a ponytail. Below (b) the inkblot has been altered with the fractal borders removed. The ability to see hidden patterns is reduced.
Fractals are patterns that repeat themselves over different size scales. The most familiar ones appear in nature, in the branching of trees, the edges of clouds, and the contours of coastlines. When the ratio of fine to coarse details is high, scientists say the image has a high fractal complexity.
“Your eyes are amazing pattern detectors, but why are they getting fooled? It’s almost as if they are getting trigger happy, seeing things that aren’t there,” Taylor told The Guardian. His work on fractals began with studies of Jackson Pollock’s spectacular drip paintings