Iconic blots of ink on today's Google Doodle honor Swiss psychologist Hermann Rorschach's 129th birthday. But over a century later, the validity of his famous psychological test—the Rorschach—depends on the eye of the beholder.

Hermann Rorschach was born November 8, 1884, in Zurich, Switzerland. His brief career included positions in several Swiss and Russian hospitals, clinics, and asylums before his appointment as associate director of the asylum in Herisau, Switzerland.

But the test that bears his name brought Rorschach enduring fame. Rorschach created it from the roots of a popular, ink stain-driven parlor game known as Klecksographie. When he noticed that schizophrenics saw the blots very differently than did others, Rorschach suggested using the card test to diagnose this disease. (Related: "Visualizing the Psychology of Attraction.")

His inkblot test and method was published for the first time in his 1921 book Psychodiagnostik—which appeared less than a year before Rorschach's untimely death of appendicitis at age 37.

Many clinical psychologists still use Rorschach cards as a projective test for determining personality and diagnosing mental illness, and the International Society of the Rorschach and Projective Methods even publishes a journal of Rorschachiana.

Here's how proponents say it works: When the viewer ponders an ambiguous blot, their mind will create its own meaning, which offers a window into the subject and their view of the world.

But other experts suggest that after a hundred years, the test has little if any place in modern psychology.

"It definitely still has this very compelling mystique," said Emory University psychologist Scott Lilienfeld, co-author of What's Wrong with the Rorschach?

"And it's fun. I still like looking at the blots. But the danger is that people can draw many conclusions that just aren't supported."

Rorschach Test Explained

The test's popularity among psychologists grew through the 1950s, then hiccuped over concerns that individual psychologists too often interpreted the same test responses in very different ways.

Those problems led to the creation of a modern, standardized version of the test established in the 1970s as the Comprehensive System, which was meant to remedy such flaws and is still in use today.

"It's still popular in some quarters of the clinical community—there's no doubt about it," Lilienfeld said. (Try National Geographic's Brain Games.)

Uncounted millions of people over the years have taken the Rorschach test.

During the test, they're shown a series of ten shapes in a set order. When asked what they see in the five grayscale and five color images, their responses are rated across a system of a hundred variables that reflect how the person perceived the blot.

Whether form or color most impacted their response may be a variable, for example, or whether they focused on specific parts instead of the whole.

While no answers are "right" or "wrong," when compared with millions of other responses, they are used to build a larger psychological profile. A tendency to focus on tiny details rather than the whole suggests an obsessive viewer, for example, while those who see movement may be impulsive, Rorschach advocates believe. (Related: "Who Multitasks Best? Women, Of Course.")

Rorschach Fundamentally Flawed?

However, many experts believe the test is fundamentally flawed.

While researching their book, Lilienfeld and colleagues combed through half a century of scientific studies and research on the Rorschach. The standard test can yield over a hundred different scores, he explained, and in their analysis only a few of them ever held much validity.

"By and large it seems to be OK, not great but OK, for assessing and detecting thought disorder or thinking disturbances," he said. "When people see odd things in the blot, peculiar objects or shapes, that is often linked to a higher probability of disorders like schizophrenia or bipolar disorder.

"But most clinicians go well beyond that," he added. "Many clinical psychologists will too often draw unwarranted inferences from it that aren't supported by the data."

The biggest problem, he added, is that the tests simply don't provide any information beyond the most basic, while that and much more can usually be learned by more practical methods. (See "Beyond the Brain.")

"Just talking to a person you can often find out if they are introverted or impulsive by asking enough questions about their behavior and how they've acted. The test doesn't seem to add much beyond that."

Personality a Stretch

It wasn't until two decades after Rorschach's death that his test was widely used to interpret personality. Indeed, the test's namesake never really promoted that use.

"His original purpose seemed to be to detect schizophrenia and other disorders,"

Lilienfeld said.

"Lots of people have gone way beyond that and try to detect personality traits like impulsivity, or even risk for criminality. In our view Rorschach doesn't do much better than flipping pennies for detecting those traits."