Does astrology work? We tested the ability of 152 astrologers to see if they could demonstrate genuine astrological skill.
Here is how the study was designed and what we found (including a result that really surprised me):
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Back in January, we ran a study trying to predict 37 facts about people's lives using their astrological sun signs (whether they are Pisces, Aries, etc.) While personality tests were able to predict these facts decently well, sun signs couldn't predict even a single 1 of them...
Some astrologers criticized us for this, saying that sun signs/zodiac signs are just tabloid astrology - real astrologers use a person's entire astrological chart.
And they're right!
Taking into account this criticism, we got the help of 6 astrologers to design a new study.
Here's how the study worked to test astrologers:
• in each round, each astrologer gets LOTS of information about a real person (answers to 43 questions) along with 5 full astrological charts
• they then predict which is the person's real natal chart (the other 4 are decoys)
Why this study design?
One of the most fundamental claims of astrology is that a person's natal chart contains information about that person's life and character.
If true, astrologers should be able to correctly choose a person's chart at a rate well above random guessing.
Each astrologer tries to match people to their correct chart 12 times. If they're guessing completely at random (e.g., they have no skill because astrology doesn't actually work), then they'll get about 20% of questions right, or about 2.4 questions right (on average) out of 12.
Neat aspects of this study design are that (1) if astrology doesn't work, it's impossible for astrologers to do better than random guessing at this task, while (2) for the study to come out in support of astrology, astrologers only need to do slightly better than random guessing
But this is only a fair test if astrologers believe they can do this task - so we limit our analyses only to participants with prior astrological experience who predicted they would do better than random guessing at the task. Our results are based on 152 such astrologers.
These astrologers were quite confident in their ability to match people to charts. Those with the least experience believed (after they had completed participation) that they'd gotten 5 out of 12 right, and those with the most experience thought they'd gotten 10 out of 12 right.
So, how did astrologers do overall? If they'd gotten even 23% of questions right (slightly above the 20% of random guessing), the study would have come out in favor of astrology. But astrologers as a group performed indistinguishable from random guessing, getting < 21% right.
We can compare how frequently astrologers got different numbers of questions correct to how often we'd expect them to get different numbers correct if they were all guessing totally at random with no skill.
The two distributions match very closely.
But perhaps the less experienced astrologers were just dragging down the performance of the group?
We looked at how performance varied based on astrological experience. More experienced astrologers did not do better than less experienced ones despite being far more confident.
Even if most astrologers have no skill, there's another way astrology could prove itself. If even 1 of the 152 astrologers performed exceptionally well, that could provide meaningful evidence for astrology. We offered a $1000 prize for anyone getting at least 11 out of 12.
Unfortunately, despite more than half of the astrologers believing that they had gotten 6 or more questions right (after completing the task), in actual fact, not a single astrologer got more than 5 right.
Okay, so despite them believing they could do this task, astrologers seemed to have no ability to match people to their astrological charts. But, even if they aren't getting the answers right, do they at least agree with each other on what the right answers are?
Much to my surprise, astrologers had very low agreement with each other on the chart for each person. If astrologers picked charts at random, they would agree with each other 20% of the time. In our study, even the most experienced astrologers only agreed 28% of the time.
In conclusion, despite believing they could do it, the 152 astrologers seemed to lack any ability to match people to their astrological charts.
You can learn a lot more about the study (including its limitations and how we sought to address them) here:
If you believe you have astrological skill, you can try the same questions that we used in the study (and find out the right answers at the end) in order to test yourself:
If you enjoyed our astrology work, you might also like our "ultimate personality test" - which analyzes your personality using the 3 most popular personality frameworks simultaneously while teaching you about how accurate (or not) those frame,works are:
1/ Is the idea of IQ legit or total B.S.? With the replication crisis in social science, it's worth asking this since a number of major psychology findings didn't hold up under scrutiny.
To find out, at Clearer Thinking, we ran a massive study...🧵
2/ We tested thousands of people performing random subsets of 62 diverse cognitive tasks (vocab, math, logic, pattern recognition, reaction time, games, memorization, mental rotation, language learning, etc.).
3/ We successfully replicated a classic finding: performance on nearly all cognitive tasks correlates positively with performance on the other tasks—a phenomenon known as the "positive manifold," foundational to IQ (blue=positive, red=negative).
The Dunning-Kruger Effect is one of the most famous psychology findings. It's the idea that people of low competence/ability overestimate their ability. But is it REAL? At Clearer Thinking, we investigated (with surprising twists and turns): 🧵
First off, "Dunning-Kruger" is sometimes used to reference a 2nd related idea: that high-competence people *underestimate* their ability (the opposite of low-competence people)
We'll explore both ideas.
What was found in the original study about these effects?
They compared people's self-estimated ability to actual percentile scores on those tasks. If people were accurate self-assessors, the black line would closely match the grey. Instead, it seems low-skilled people overestimate their skills, and high-skilled ones underestimate:
Being one of history's most successful entrepreneurs is quite a different skill than making predictions about the future. So, I wondered how accurate Mսs𐔘's predictions are. I spent hours finding as many of them as I could, aiming to be as even-handed as possible:
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Overall, I identified 50 predictions about the future he'd made for which it was confirmable whether they'd been correct. I skipped predictions that were too ambiguous to judge.
So, how did he do?
20% were correct predictions, and 80% were wrong.
How good or bad is this?
On the one hand, some of the things he is attempting to predict are hard to predict, so one might expect anyone to be wrong often. On the other hand, if we assume that he's at minimum 50% confident when he makes a public prediction, he ideally should be getting >50% right.
If you're convinced that astrology doesn't work at all (e.g., by studies like ours, where we tested 152 astrologers and found they were no better than random chance at matching people to charts), that raises an interesting question: why do astrologers believe astrology works? 🧵
1st hypothesis: they know astrology doesn’t work and lie for profit. But that seems very unlikely: many rely on it themselves and do it for friends/family. While surely there are some charlatans, most seem totally and genuinely convinced. So, what else could explain their belief?
2nd hypothesis: they're using "cold reading" without realizing it. I suspect astrologers often are very observant and make a number of fairly accurate inferences about a person that they then misattribute to the chart.
But don't the charts tell the astrologer what to say?
There’s a really interesting debate raging in the field of genetics about how heritable different human traits are. It could end up overturning 100 years of research:
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First off, what is heritability? It’s the fraction of the variance of a trait (in a particular population) that’s caused by genetic differences.
Everyone agrees that height is at least fairly heritable since, in most populations, much of the variation is attributable to genes.
A classical and very commonly used way to estimate the heritability of a trait is to compare how similar that trait is among identical twins relative to how similar it is among fraternal (non-identical but same-sex) twins.
Are there false memories that many people share (i.e., a "Mandela Effect")? For instance, is it true that people systematically misremember which of these is the actual "Mr. Monopoly" man? We recently ran a replication of a study designed to test these claims:
[megathread]🧵
Before I get into the results of the study, here's a pop quiz. See if you can tell which of these is real and which is a collective delusion (the answers are at the bottom of the thread):