Can astrology tell us anything about our personalities?
Short answer: no. Longer answer: read on!
There are lots of ways of measuring personality, but one of the most common ones is the Big Five [i]. As you may have gathered from the name, this theory says that there five major personality factors: openness to experience, conscientiousness, extraversion, agreeableness and neuroticism, which can be remembered by the handy acronym OCEAN. You can be high, medium or low on each of these factors. I’ve put a quick summary below – in each of the scales the first thing I mention is the low end of the scale.
Openness to experience can be thought of as a scale from consistent in your tastes to curious to try new things.
Conscientiousness is a scale from careless to organised.
Extraversion is a scale from reserved to outgoing.
Agreeableness is a scale from friendly to detached.
Neuroticism is a scale from nervous to confident.
Now for the astrology bit. I’ve used the Western astrological system, since I’m most familiar with it, but other astrological systems are available. I'm a Capricorn, so according to astrology.com I should love tradition, and am conventional, business-like, efficient, inhibited and unforgiving. How does that translate to Big Five terms, and how do I stack up compared to this description of a Capricorn?
I am not much like a “typical” Capricorn, it seems. This is not a great start to astrology having anything to say about who I am, at least, but we need more data because maybe I am an outlier, the Spiders Georg of Capricorns.
An aside about outliers
In statistics, outliers are datapoints that look nothing like the rest of the datapoints. For example, imagine you're interested in how fast humans can run a distance of 100 metres. To check it out, you go to your local park. You see lots of people who take somewhere in the range of 15-25 seconds to run the distance. OK, you think, the slowest people take 25 seconds to run that far. That means that I should get dinosaurs who run slower than that for my Free-Range Dinosaur Amusement Park and 24-Hour Waffle House, maybe slower than 30 seconds to be on the safe side in case someone's using crutches.
Now imagine you didn't have much time because you had to order whipped cream for your 24-Hour Waffle House, so you just watched one person run and then called it a day. In a weird coincidence, you see Usain Bolt out for a run and you go home thinking that dinosaurs who take longer than 10 seconds to cover 100 metres will be perfectly safe. This is why it is a silly idea to draw your conclusions from just one datapoint.
Back to astrology. Let's look at a couple of studies on astrological sign and personality that ask about the experience of more than just one person.
Let’s say we ask asked 241 university students in New Zealand about their zodiac sign and their neuroticism and extraversion levels and find no evidence of any link between sign and personality [ii]. That could just be a coincidence, you say, that’s only 241 people. OK, how about a study [iii] of over 65,000 South African jobseekers? Still no!
You will keep getting a no if you keep searching [iv] [v]. There are a few studies that say there is a link between zodiac sign and personality like this one claiming that personality differences between twins can be explained by differences in their astrological charts at the exact moment of birth [vi], though they’re often debunked later [vii]. (In the spirit of fairness, here [viii] is a link to a rebuttal of the debunking; make up your own mind.) But in the very large majority of the studies that have explored this topic, the answer to the question Can astrology tell us anything about our personalities? is a resounding, “Lol no.”
Why do some people believe that the answer is, “Heck yes,” then?
Let’s look at a study of a couple of hundred Dutch people who were given one questionnaire on their astrological knowledge and another on their personality characteristics [ix]. In this study, people born under an air sign (Gemini, Libra, Aquarius) or a fire sign (Aries, Leo, Sagittarius) had a higher extraversion score than those born under an earth sign (Capricorn, Taurus, Virgo) or a water sign (Cancer, Scorpio, Pisces). This does actually fit with astrological theories about personalities, but here’s the thing: that pattern is only seen among people who have high astrological knowledge. This might be a self-fulfilling prophecy: you, a Libra, read that you are supposed to be outgoing and you start noticing instances when you are outgoing much more than when you are reserved – and then, when someone asks you to define yourself as outgoing or reserved, you remember all the times you were outgoing much more strongly than all the times you weren’t.
It’s probably safe to say that you only display the stereotypical characteristics of your astrological sign if you believe that you will. But as a business-like and conventional Capricorn, I was bound to come to that conclusion.