One thing I have noticed since I started learning astrology is that a lot of people don’t feel like their Sun sign. Leo Suns ask why they feel introverted and don’t relate to their extroverted, attention-loving stereotype, and although the “you need to consider your whole chart” and “these are just stereotypes” answers are very much true, they don’t explain the phenomenon, a least not in a satisfying way.

So I decided to do some research. I was already familiar with some astrological indicators. For example, the level of extroversion someone tends to present with is often associated with the following zodiac signs: Aries, Leo, Aquarius, Libra, Gemini, and Sagittarius, and introversion is associated with the remaining Zodiac signs (Taurus, Cancer, Virgo, Scorpio, Capricorn, and Pisces). Or in other words, Fire and Air signs are more extroverted, while Earth and Water signs tend to be more introverted. However, I wanted to see if this actually had any weight to it.

A data driven approach

Since I’m a data nerd, I was delighted to come across a Reddit post from earlier this year: Tell me your big three and your Myers-Briggs type. It had 769 comments, where people shared their Sun, Moon, and Rising sign along with their MBTI type. A quick search found many more similar posts, so I naturally started collecting the data. After carefully processing the data: standardizing responses, getting rid of duplicates (from the same reddit username, or deleted accounts), and removing responses with incomplete data, I arrived at a dataset of 1462 unique responses. Here’s what I found.

The Statistical Test

Note: If you’re not that interested in the technical statistics, I’d skip over this section and go straight to the summary section.

The objective of this statistical analysis is to determine if someone’s astrology big 3 (Sun, Moon, and Rising sign) has any relationship with introversion or extroversion.

The Null Hypothesis: A person’s extroverted or introverted traits are independent and unrelated to their astrology “Big 3” placements of Sun, Moon, and Rising signs. The expected distribution is that extroversion and introversion will be approximately the same rate across all categories (zodiac signs and elements), similar to the total distribution of extroversion and introversion in this dataset.

We set the confidence level to 95%. This means that to reach statistical significance, we need to see a p-value of less than 0.05 to reject the null hypothesis and say there is a relationship.

Method: Pearson’s Chi-Squared test was used to see if there’s a relationship between Sun, Moon, Rising sign independently, by element, and in combination with each other (e.g. Dominant element among the 3 placements). Furthermore, additional Pair-Wise Pearson’s Chi-Squared Tests were performed with the threshold p-value adjusted downward accordingly, this was to identify which specific effects of the signs/elements were statistically significant.

The Results

Introverts were overrepresented  (71%) in this population compared to Extroverts (29%). 

We have an imbalanced dataset here, since the general population has a more even split of 51% introverted and 49% extroverted. I wasn’t sure if the heavy introvert skew was due to an interest in astrology itself or Reddit in general, but it seems like the MBTI subreddit has shown a similar skew of: 69% introverts vs 31% extroverts.

This is what was found for the effect of Sun Sign:

Chi-square test	Result
Pearson Chi-square ( 11.0) =	24.5056
p-value =	0.0108
Cramer’s V =	0.1295

For the Sun Sign test, we can reject the null hypothesis. It is highly unlikely for the null hypothesis to be true since the difference in distribution is statistically significant at p-value=0.01. This means the Sun sign may be correlated to levels of extroversion or introversion. We need to do further testing to identify what could be influencing this.

Further testing shows that both the Sun Sign Element type and Dominant Element type support rejecting the null hypothesis since both of the distributions are unexpected and statistically significant with of p-value=0.0041 and p-value=0.0073, respectively.

Chi-square test (Sun Sign Element)	Results
Pearson Chi-square ( 3.0) =	13.2682
p-value =	0.0041
Cramer’s V =	0.0953

Chi-square test (Dominant Element)	results
Pearson Chi-square ( 3.0) =	12.0269
p-value =	0.0073
Cramer’s V =	0.1160

Sun Sign Element Charts:

Dominant Element Charts:

Additional testing was done to check for significant factors for each Sun Sign Element and Dominant Element. This was done using Pair-Wise Chi-Square test.

Since we tested multiple combinations on the same categories of a single dataset, we need to adjust the acceptable p-value. We divide the original p-value threshold of 0.05 (95% confidence) by 6 (total number of tests being performed) to get a new p-value threshold of 0.00833. 

I didn’t think I’d find anything statistically significant with this new p-value threshold, but I was surprised…

Fire Suns (Aries, Leo & Sagittarius) are significantly more likely to be extroverted, when compared to water sun signs

p-value = 0.0005

Water Suns (Cancer, Scorpio & Pisces) are significantly more likely to be introverted, when compared to fire sun signs

p-value = 0.0005 

A Fire Dominant Big 3 are significantly more likely than Water Dominant individuals to be extroverted

p-value =0.0019 

A Water Dominant Big 3 are significantly more likely than Fire Dominant individuals to be introverted

p-value = 0.0019

Summary of Findings

Is there a relationship between astrology and the level of extroversion or introversion? Yes, it seems like there is. There is a statistically significant relationship between astrological factors and extroversion and introversion, with 95% confidence.

If you have a Fire Sun, you are statistically more likely to be an extrovert compared to water-based sun signs, and vice versa (Water Sun signs are statistically more likely to be introverts)

If you have a Fire Dominant Big 3, meaning if 2 out of 3 of your Sun, Moon, or Rising are in fire signs, you are statistically more likely to be an extrovert compared to water dominant people, and vice versa (Water Dominant Big 3 are statistically more likely to be introverts)

All other combinations did not have a strong enough influence to have any statistical significance. That means if you have any of the following, extroversion and introversion traits are statistically equally likely for you: 

• If your Sun sign is an Earth or Air sign
• If you don’t have a dominant element in your big 3 (it’s a balanced mix)
• If your Dominant element is Earth or Air

The Moon Sign/Element and Rising Sign/Element by themselves did not have any statistically significant relationship with extroversion and introversion. 

Although the type of data collected and analyzed here differs, these findings are in line with two out of three research papers (see links below) that explored the relationship between astrology, extroversion, and introversion.

One of these studies mentions the possibility of people answering personality surveys in a subconsciously biased way, answering them in line with their zodiac sign stereotyped traits. This is based on the assumption that many of the participants knew their zodiac sun sign was associated with extroversion or introversion traits and answered accordingly.

This could potentially explain the findings, especially since the data I analyzed is sourced from a community of astrology enthusiasts. However, I assume this is not true for everyone, or even most people. I, for example, knew my MBTI many years before I learned my astrology Moon and Rising. When I took the MBTI test, I only knew I was a Capricorn Sun at the time, and had no idea it was associated with introversion. 

Another problem with this theory is that subconscious bias doesn’t quite hold for the Air and Earth signs. It doesn’t explain that extroversion and introversion are only statistically significant for Fire and Water sun signs/dominant people. Plus, there are still many astrology enthusiasts scratching their heads, wondering why they don’t feel like their Sun, Moon, or Rising sign.

I’d love to do another analysis using full natal charts sometime, but I’ll have to get my hands on an appropriate dataset first!

For those who are interested, I’ve published the dataset here: Astrology Big 3 and MBTI

Reference Research Papers

An Empirical Study of the Relation between Astrological Factors and Personality – J. Mayo , O. White & H. J. Eysenck (1978)

Introversion-Extroversion and Astrology – Marlin Jackson, Martin S. Fiebert (1980)

Can Extraversion (E) and Neuroticism (N), as defined by Eysenck match the Four Astrological Elements – Robert Currey (2017)