Droplets of blood fall and bloom in the trailer for the upcoming Netflix psychological thriller series Mindhunter. Between shots from the show, which will explore the FBI’s partnership with serial killers when it premieres on October 13, the drops expand and gather into symmetrical blotches, forming the well-known shapes of a Rorschach test. For some viewers, they may seem to pool, eventually, into a very familiar pattern. If you start seeing an agonized face in the crimson splotch, you’re not the only one.
The Rorschach test was developed in 1918 by Swiss psychologist Hermann Rorschach, who made the ink blots himself by dribbling ink onto paper and folding them in half. Rorschach, who believed the test could help psychologists understand their patient’s perception and mental grasp, asked people what they saw in the blots and then analyzed their responses. What he was really doing was exploiting a natural phenomenon called pareidolia, which occurs every time we see things that aren’t actually there.