The Skeptic Next Door

I have been reading a paper published in the Journal of Consciousness Studies, 10, No. 6-7, 2003, pp.175-198 “Is Astrology Relevant to Consciousness and Psi?” by Geoffery Dean and Ivan W. Kelly. Dr. Kelly was kind enough to send me a copy.

The paper is partially a survey of other papers and a reanalysis of an experiment conducted in 1985. Specifically they investigated the conjunction between astrology and intuition or psychic ability of astrologers. By astrology they mean “real” astrology where abirth chart is drawn up based on the subjects date and time of birth. Not the daily sun sign horoscopes printed in newspapers.  I am going to focus on this experiment.

In reading birth charts many astrologist report using intuition/psychic ability in preparation of a reading for a client.  The experiment evaluates the difference in ability between the intuition/psychic astrologers and those who do not use such skills.

Experiment

Astrologers

45 from a range of countries, ages, and years of experience

Subjects

160 subjects were selected from a pool of 1198. The selected subjects had an average age of 30 (range 15-66), 72% were female, and 46% were university students.

Subject Selection

The subjects took the Eyesneck Personality Inventory.  The selected subjects scored in the top and bottom 6.67% for extroversion/introversion and psychoticism (tough-minded and uncaring/tender-minded and caring).  The average scores for the selected subjects were seven standard deviations from the overall average. 40 subjects were at one of the two extremes on the extroversion scale, 40 at the extremes of the neuroticism scale and 80 were on the extreme ends for both scales. The astrologers agreed that these personality attributes would be reflected in the subject’s charts and would be easy or moderately easy to determine.

Experiment

Based on the subjects’ birth chart the astrologers determined how the subject scored on the personality inventory for the two scales. The astrologers determined if each subject was high, low or none for each extraversion and psychoticism rating.

Data Collected

Astrologer’s determination of the subject personality, how long it took to make the determination, how confident they were in the determination.

Results

• Where the Astrologers who use intuition/psychic abilities more accurate? No, there was no significant difference between those that relied on intuition or psychic abilities.
• Were the astrologers accurate? No, the effect size was, 0.01 or approximately 50.5% vs. 50.0% by chance.  Range -0.01 to 0.02 for both extraversion and neuroticism. The range for the agreement and accuracy is based on grouping the astrologers’ amount of intuition.
• Did the astrologers agree? This needs a little explanation.  If astrology is a science based on a date and time of birth, different astrologers reading the same chart should agree, even if they are lead to the wrong conclusion.  For extroversion there was some agreement, the effect was 0.12 to 0.17 but for neuroticism the agreement was 0.00 to 0.05.
• When astrologers agreed, were they more accurate? When the judgments were ranked by astrologer agreement.  The correlation for the top third was 0.01 and -0.01 for the bottom third.
• Did astrologers who were more accurate on the first half of the subject do as well on the second half?  No, they tended to revert to the mean, correlation -0.13.
• When the astrologers were more confident in their determination were they more accurate?  No, Extraversion 0.00, 0.03 and -0.02 for low, medium, and high confidence.  For neuroticism the effects were 0.05, 0.02 and -0.04.
• Does astrology only work for some people?  For the group of 80 subjects who were at extremes for both scales, if astrology worked for some of them then the astrologers should be correct on both attributes.   This should show up as a positive correlation.  Unfortunately the correlation was 0.02.

Summary

This was a dismal result for astrology.  It was not accurate, there was no effect based on confidence or claimed intuitive abilities.  There was a trivial amount of agreement between astrologers for only extraversion.  The correlation of 0.17 is very low, and higher agreements did not have higher accuracy. In the experiment neither psychic or non-psychic astrologers had any predictive power with regards to subjects personality.

This entry was posted on Monday, December 8th, 2008 at 5:28 am and is filed under Atheism, science, Skeptic Escapes. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.