Forer served as a psychologist and administrator in a military hospital in France during World War II.

Upon return he worked in a Veterans Administration mental clinic in Los Angeles; and in private practice in Malibu, California.

Rather than scoring the tests and giving individual assessments, he gave all the students exactly the same analysis copied from a newspaper astrology column.

[4] The "Forer effect", sometimes known as the Barnum effect, shows that people tend to accept generalised descriptions of their personalities without realising that the same evaluation could apply to nearly anyone else, because people want the results to be true.

This experiment is frequently cited in criticisms of other personality tests like the Myers-Briggs Type Indicator.