STATS ARTICLES 2003
Rorschach For Dummies
April 29, 2003
A case study in psychological bias
The Rorschach psychological test - AKA the inkblot test - was developed by its namesake from a European party game at which he excelled. Although the American Psychological Association reports that 82% of its members use it occasionally to help diagnose their patients and 43% use it frequently, The New York Times Magazine, in its "Crash Course" column suggests that it is about as accurate as other party-time entertainments such as Tarot cards.
And covering the release of a recent book criticizing the research base for the test, "What's Wrong with the Rorschach," by James Wood et al. (Jossey-Bass, 2003), the Times' magazine debunks yet another widely accepted psychological icon. The authors believe that the Rorschach may have some highly limited uses, but is "vastly overrated."
In an excerpt presented as a sidebar, they discuss several important biases which help account for the persistent popularity of the test, and which should be understood by people who want to think critically about psychology.
The first is "confirmation bias." This occurs when someone tries to test his or her own theory on an unselected sample, usually his or her patients, friends or family. What happens here is that the person tends to recall and emphasize the cases that confirm the theory, while forgetting, dismissing and/or inventing reasons why the cases that don't aren't relevant.
A related bias is the "illusory correlation." Here, the clinician recalls the cases where the theory correctly connects, for example, a picture drawn by the patient, and a particular diagnosis, but ignores or forgets those more common situations in which it is incorrect.
The final bias mentioned is the "overpathologizing illusion." Psychologists want to make a diagnosis - not send someone away, saying "that's just normal, you're OK." One may interpret this generously as an impulse to be "better safe than sorry," or ungenerously by pointing to their economic interests.
Either way, tests that are developed with norms set by studying the actual prevalence of symptoms in the general population will by definition find most people normal. The Rorschach, however, can find some darkness or need for help related to almost any interpretation of the blot - and this "overpathologizing" makes it more popular with clinicians.
For more on the Rorshach, there are two groups devoted to promoting it, Rorschach.com and Rorschach.org, and one group that has gotten into trouble with them for publishing information about how psychologists interpret the test. (This is supposed to be secret because otherwise people could "fake" the test.)
A PDF of a Scientific American article by several of the book's authors criticizing the Rorschach and several other "projective" psychological tests (those which require the subject to make subjective interpretations of ambiguous stimuli) is also worth examining. And, if you have the inclination, there is also a spoof Rorschach test online.