Despite identifying as a bona fide skeptic, I admit I know my zodiac sign. I celebrate my birthday in early November, and every now and then someone reacts to that information with an assertive, "I just knew you were a Scorpio."
If you could really tell, then why didn't you say something before I mentioned it? And besides, what is it that I exude that verifies my Scorpiosity? What is a Scorpio anyway?
That I should have something in common with Joni Mitchell, Joan Sutherland and Mary Travers (of Peter, Paul, and ...) who were all born not only under the Scorpio sign but on the same day as I, boggles my mind. I cannot carry a tune, not even in the shower.
According to the Urban Dictionary, "Scorpios are the people most likely to denounce stuff like astrology ... they are serious and skeptical people." Well, maybe there is something accurate about horoscopes after all. So, let me fulfill my Scorpion destiny and look critically at what we know about horoscopes and zodiac signs.
In a classic 1948 experiment by psychologist Bertram Forer, subjects completed a personality test and received a written assessment of their results. Forer asked them to rate the accuracy of their personal profiles; the result was very high ratings (an average 4.26 where 5 is "very accurate").
However, each person received the exact same assessment that Forer took from a newspaper horoscope: "You have a need for other people to like and admire you, and yet you tend to be critical of yourself. While you have some personality weaknesses you are generally able to compensate for them. You have considerable unused capacity that you have not turned to your advantage."
What Forer discovered was that people have a tendency to accept vague and general statements as accurate about themselves without the benefit of any objective measurement. When empirically false statements sound positive, they will agree that the traits describe them accurately. This subjective perception is sometimes called the Forer effect.
But since P.T. Barnum is believed to have said "we have something for everyone," psychologists often label this process of subjective validation as the "Barnum Effect."
Take a simple test to illustrate. Decide how well this statement describes you: "You like work that is meaningful and dislike demeaning jobs; you prefer the truth and you dislike shallow relationships." Sound familiar? Yet according to an online astrology website, these are typical Scorpio characteristics.
Over 60 years of research continue to verify that people read into horoscopes what they want to believe. Perhaps there's no harm in that, if what you read motivates you to achieve your goals, to find happiness with loved ones, and to avoid making life-threatening mistakes. (Ouch, I'm starting to write like a horoscope.) Research has consistently verified the existence of subjective validation, so let's look at horoscope research from a different angle. Can different zodiac signs objectively distinguish people's opinions and behaviors?
Data from the General Social Survey — the largest random sample source of the Americans' opinions, collected regularly since 1972 by the National Opinion Research Center in Chicago — include information about respondents' astrological signs. Using this dataset, I ran some statistical tests evaluating differences among the 12 zodiac signs on several different criteria. Since many horoscopes indicate some people born under certain zodiac signs are more outgoing and better at making friends, I used GSS items asking about differences in the number of good friends respondents have, the number of close friends they have in the workplace, and the number of friends close enough to discuss problems. The differences among all 12 groups for each of these three items were not statistically better than chance.
Scorpios, for example, did not have more or fewer close friends than people born under any other sign.
Psychologist Charles Reichardt also found similar weak relationships between zodiac signs and political views. Intrigued that the horoscopes on an online website suggested that Taurus, Sagittarius and Virgo people tend toward conservatism, he looked at 40,637 respondents in the GSS dataset and found no statistical difference in identifying oneself as liberal, conservative or moderate among the 12 zodiac signs. Using several other measures, Reichardt concluded that "astrology provides little if any basis for accurately describing individual human differences."
Even professional astrologers, however, might pooh-pooh mass market horoscopes. So researchers John McGrew and Richard McFall conducted a more elaborate study in 1990 going beyond simple newspaper horoscopes and focused on detailed astrological charts.
They had six expert astrologers and one nonastrologer attempt to match the birth chart horoscopes (prepared by professionals from the Indiana Federation of Astrologers) of 23 people to their case files, which contained life histories, photos and results from a standardized personality assessment and a vocational interest inventory.
Now predict the outcome! You got it: None of the six astrologers was able to match the 23 astrological charts with the 23 case files better than the one nonastrologer or by chance alone. More embarrassingly, there was very little inter-astrologer agreement.
Reading horoscopes can be fun and entertaining. But using what they tell us, or what an astrologer might derive from a detailed and expensive birth chart, requires critical-thinking skills before acting on the readings. How would the alignment of stars and planets affect your personality? Why would a Scorpio born in 1906 have the same horoscope characteristics as a Scorpio born in 2006? And what could I possibly have in common with Joni Mitchell?
In any case, have a happy birthday fellow skeptical Scorpios. Remember we do have some things in common: We were all born under the best sign and critical thinking brought us to that undeniable conclusion!