Hans Eysenck Study of Astrology

Professor Hans Eysenck (1916–1997) was a most influential psychologist of his time. His PhD thesis, completed in 1940, looked into how artistic judgement and taste (for pictures, for poetry) varied among individuals. He found that there was some objectivity to artistic judgement, and hence good and bad judges.

He aimed to develop a scientific understanding of personality.

Eysenck was involved with astrology mostly during 1975-1985. His interest in astrology was aroused by the findings of Michel Gauquelin (1926-1991). Eysenck was impressed, and later came to argue that astrology makes testable assertions such as those linking planetary positions and personality.

Eysenck assessed the evidence, commenting that "the time that is wasted is mine, and to waste it by reading the literature on astrology and parapsychology is probably better spent than in watching pornographic films, or becoming a football hooligan!" (1986, 382-383)

Eysenck also became involved in a test of sun signs. In 1971, the British astrologer Jeff Mayo had sent Eysenck a study of 1795 subjects in which their mean scores on Mayo's extraversion questionnaire were plotted against sun sign. The results showed a zig-zag pattern completely in accordance with astrology. Eysenck was intrigued and made the EPI [Eysenck Personality Inventory] available to Mayo for further tests. The outcome was a paper by Mayo, White and Eysenck (1978) detailing the EPI results for 2324 subjects, followed in the same journal by a paper by Smithers and Cooper (1978) detailing the EPI results for 559 students. In each case the result was a zig-zag pattern in agreement with astrology.

Advance notice of the Eysenck paper was hailed by astrologers as "possibly the most important development for astrology in this century" (Phenomena 1977, 1, 1). But Eysenck later discovered that the effect disappeared when people unfamiliar with sun-signs were tested. The bias may be unconscious and very slight.

In the late 1970s Eysenck and David Nias began a survey of the scientific evidence for astrology. The result was the book Astrology: Science or Superstition? (Eysenck and Nias 1982), which covered astrological principles, sun-signs, marriage, illness, suicide, appearance, time twins, season of birth, terrestrial and solar cycles, radio propagation, earthquakes, and lunar effects. In 1986 the book appeared as a Penguin edition.

Apart from reviewing the evidence for astrology, Eysenck and Nias made two original and important refutations, both of which were subsequently confirmed by others. First, the Mayo zodiac effect was shown in two separate studies to be an artefact of prior knowledge. Second, the claims of John Nelson (that planetary positions can be used to predict shortwave radio quality with about 90 per cent accuracy) were shown to rest on an artefact in calculating the accuracy rate.

Eysenck and Nias were able to point to that much of the acceptance of astrological readings was explained by the Barnum effect. Eysenck: "If the most basic tenets of astrology are true, they should be detectable in their own right . . . If astrology is true, it must pass that kind of test."

When he delivered his revised verdict on the Mayo study during the 1979 astrology conference at the Institute of Psychiatry, "there was a strong feeling among some of the astrologers that Eysenck had first beguiled them with his patronage, and then betrayed them by bringing forward some ugly facts" (Gibson 1979, 210, cited in the orbituary by Dean and Nias).

Eysenck wrote several papers on research methods in astrology, but he doubted that research could be taught via cookbooks.

Eysenck became the world's most cited living psychologist, and (after Freud and Piaget) the most cited psychologist of all time. There can be few astrological researchers that he was not an inspiration to.

[Abstract from an obituary by Geoffrey Dean and David Nias 1997]