My Top 10 Posts of 2025
...and reflections on my second year on Substack
In Case You Missed It: Good Things Come in Twelves…
12 Viral Graphs Featured in The Nature-Nurture-Nietzsche Newsletter
12 New Findings on Love and Romance
Reflections on My Second Year on Substack
It’s now been just over two years since I decided to get started on Substack. I made the decision for several reasons. One was that Twitter/X was becoming a lot less fun than it used to be. Another was that I’d started hearing rumors about how lucrative Substack can be.
But the most important reason was self-protection. As I discuss in my forthcoming book A Billion Years of Sex Differences, an academic paper I wrote in 2021 with Lewis Halsey about sex differences in STEM stirred up a minor controversy online and got me reported to the DEI administrators at my university. Nothing much came of it, but I was somewhat shaken. I decided I needed a backup plan - a way to make myself cancellation-proof.
The plan I came up with was to establish a second career on Substack. I think it’s fair to say that this wasn’t a particularly realistic plan. Sure, some people were earning big bucks on the platform. But most weren’t, so it was a long shot. Once in a while, though, a long shot pays off, and through a mixture of luck and stubbornness, this one did for me.
I opened up the option of paid subscriptions on January 3, 2024. I didn’t have a definite goal in mind, but I did have a few hazy ones. One hazy goal - actually, more an “imagine if” than an actual goal - was to match my professor salary within a year. I didn’t seriously expect to achieve this. But by a bizarre coincidence, on January 2, 2025, at ten minutes to midnight, I got the last paid subscriber I needed to do just that. In other words, I crossed the finish line for my ridiculous, not-really-a-goal goal with only ten minutes to spare.
Growth has been somewhat slower this year. It’s been steady, though, and a few months ago, I hit another milestone: 1,000 paid subscribers. As the year comes to a close, I’m now earning considerably more from Substack than from my “real” job. So, although I am still a psych prof, I no longer need to be. I could walk away at any time.
It’s hard to overstate the sense of freedom this gives me. I’ve always tried to write honestly and openly about the topics I’ve covered, even when I’ve known it wouldn’t be popular. But I do so now with considerably less trepidation.
Substack is much more than a backup career, though. Since I was a child, I’ve dreamed of making a living as a writer, but it was never a realistic possibility. Substack has made it one.
Moreover, writing on Substack has many advantages over traditional writing. First and foremost, there are no editors deciding whether to publish what I write or trying to change my words. On the one hand, this does make it easier for me to say something stupid that gets me into trouble. On the other hand, it’s great not having to haggle over my writing, and being able to say exactly what I want.
My plan is never to retire, but to work until the day I die. Retirement age is still a long way away, and I reserve the right to change my mind - but that’s my current intention. I doubt, though, that I’ll want to be a psych prof till then, or to pursue any other traditional career. Writing on Substack seems like a great way to continue contributing to the world well into my golden years. I hope you’ll join me for at least some of that journey!
My Top 10 Posts of 2025
Let’s get to the main event: my Top 10 posts of the year. Note that most of them are partially paywalled, but some are free to read in full (as indicated).
10. 10 Highly Replicable Findings from Psychology
The replication crisis in psychology has dented many people’s confidence in the field, my own included. But plenty of findings have survived the challenge. In this post, I share ten of my favorites, covering topics as diverse as sex differences, evolutionary psychology, behavior genetics, IQ, and personality. Long story short, not everything you were taught in intro psych was false!
9. 12 Things Everyone Should Know About Behavior Genetics
My “12 Things Everyone Should Know” series was once again the newsletter’s most successful feature, occupying four of this year’s Top 10 spots. In this installment, I survey one of the most successful areas in psychology: behavior genetics. Among other things, I summarize evidence that heritability often increases rather than decreases as people move from childhood to adulthood, that growing up together often doesn’t make people any more similar than they’d be if they grew up apart, and that not only traits but also environments are partially heritable. (See also my 2024 series on the Four Laws of Behavior Genetics.)
8. How Intelligence and Personality Shape Our Career Trajectories [Free Post]
How do our IQs and personalities shape the jobs we choose - or the jobs that choose us? This post summarizes a fascinating study exploring the connections between cognitive ability, personality, and occupational choice. If you want to know the occupations with the highest and lowest average IQ scores, and the highest and lowest scores on each of the Big Five personality traits, this post has you covered.
7. The Genetics of Same-Sex Sexual Orientation [Free Post]
This piece outlines five key discoveries about the evolutionary genetics of same-sex sexual orientation. Did you know, for example, that the heritability of same-sex sexual orientation is surprisingly low; that it’s a product of many thousands of gene variants rather than just one or a few; and that although same-sex sexual behavior is common in other animals, same-sex sexual orientation is extremely rare?
6. Everything You Wanted to Know About Sex Differences But Were Too PC to Ask
This is the first excerpt from my forthcoming book, A Billion Years of Sex Differences. Over the next six months, I’ll be publishing around half the book for paid subscribers to The Nature-Nurture-Nietzsche Newsletter, ahead of the book’s release in June. Here’s what I cover in this installment:
The most common sex differences in our species - or what I call the “standard-issue sex differences”
Why many sex stereotypes are surprisingly accurate
Why the nature-nurture question is actually two questions, not just one
Why humans are very different from peacocks, deer, and other familiar icons of sexual selection
Why, when it comes to mating and childrearing, humans are more like the average bird than the average mammal
5. 12 Things Everyone Should Know About the Big Five Personality Traits
In this installment of the “12 Things Everyone Should Know” series, I do a deep dive into the research on the Big Five personality traits. The post covers everything from hidden sex differences in personality to how your personality shapes your success in life to how you can change your Big Five trait levels. On top of that, it looks at evidence that the heritability of personality is higher than we previously thought, and that each Big Five trait breaks down into two major sub-traits or aspects.
4. 12 Things Everyone Should Know About Violence
Another “12 Things” post! This one explores the science of human aggression. Among other things, it covers the nature and nurture of aggression, how IQ relates to violence, and the counterintuitive finding that women are sometimes more aggressive than men in relationships.
3. Personality and Intelligence Are More Closely Linked Than We Thought [Free Post]
Do intelligent people have different personalities than their less intelligent peers? Does personality shape intelligence, or does intelligence shape personality? Or is it a bit of both? In this post, I break down two recent papers tackling these issues, and highlight their agreements, disagreements, and implications. I also share some tips on how to read psychological research - especially when different studies come to different conclusions.
2. Fifty Years of Twin Studies
This one is an overview of a meta-analysis of more than 50 years of research and nearly 3,000 publications covering 14 million twin pairs. It outlines five striking discoveries about the nature of nature and nurture - among them, that every trait is partially heritable, that physical traits are more heritable than behavioral ones, and that the home you grow up in has surprisingly little effect on how you turn out.
1. 12 Things Everyone Should Know About the Psychology of Victimhood
My most popular post of 2025 was my 12 Things post about the psychology of victimhood. In it, I explore what the latest research reveals about the victimhood mindset: how it distorts our view of the world, encourages bad behavior, and poisons intergroup relations.
Honorable Mentions
As well as one-off essays, I ran various series in 2025. These included:
A three-part series on free will and whether we have it.
A two-part series on gender gaps that favor women rather than men:
A series of posts summarizing new findings in important areas of psychology, including:
My monthly Linkfest series. The most popular ones this year were:
An Early Christmas Present
As a Christmas present for all my subscribers, I’ve republished one of my favorite paid posts from 2025 as a freebie. The piece is my third most popular post of the year, titled “Personality and Intelligence are More Closely Linked Than We Thought.” Click the link below to read it!
Special Christmas Offer
My special Christmas offer is available until December 26. Act now and get 20% off a premium subscription for a year!
Gift Subscriptions
Gift subscriptions are now available to The Nature-Nurture-Nietzsche Newsletter - the perfect gift for every man, woman, and child on the planet!
What You Get with a Premium/Gift Subscription
Full access to all content, including ideas and material I don’t want to publicly share yet
Full access to excerpts from my forthcoming book, A Billion Years of Sex Differences
Full access to my “12 Things Everyone Should Know” posts, Linkfests, and other regular features
The ability to post comments and interact with the N3 Newsletter community
Finally, by becoming a paid subscriber to The Nature-Nurture-Nietzsche Newsletter, you’ll help support my efforts to spread important ideas and knowledge, and to make a space for free thought and non-politicized science.
Plans for 2026 and Beyond
I’ve got lots of exciting content planned for the coming months and years, including more excerpts from my book, A Billion Years of Sex Differences, plus essays on the evolutionary mystery of mental illness, how nature shapes nurture and nurture shapes nature, and why I’m not a Freudian.
Thanks again to everyone who’s supported me in 2025 - in particular, my premium subscribers, who’ve given me the financial security to speak freely, and the option of making a career from my writing!
From the Archive
My Top 10 Posts of 2024
Update: You can now listen to Nature-Nurture-Nietzsche-Newsletter posts as well as reading them, with Substack’s new text-to-speech feature. I’ve opted for the British accent rather than the American one - but let me know if you’d prefer the American!
A quote from last year’s Top 10 roundup:
As my Substack guru Rob Henderson once wrote, “One of my favorite things about writing on Substack is that every time I share something useful, interesting, or entertaining, I get a raise.”
This makes writing on Substack very different than being a psych prof. As a professor, you get paid even if you give the occasional dud lecture - and although I do my best to make my lectures interesting, I’m aware that many of my students are only really there because they think it’s necessary to get a degree these days to get anywhere in life. In contrast, no one has to pay for a Substack subscription if they don’t want to. That means that every dollar earned on Substack is an immediate and honest signal that you’re producing something people value.
Fantastic story Steve. Good on you. And an inspiring story as well. Being a scientist in the field of evolutionary psychology the freedom to write what you want is nowadays invaluable. I look forward to your road ahead. There are so many lessons to be learned also for my field pedagogical sciences/rearing children where the Blank Slate is sadly still alive and well. The main reason I started my own Substack-newsletter: to enlighten the Dutch. Thanks for all the inspiration (The Ape That Understood the Universe is a personal favourite), walk on, and good luck with the Nature-Nurture-Nietzsche Newsletter.
One of the giants of primatology the Dutch-American ethologist Frans de Waal - who sadly passed away last year - made a bold prediction in 2002:
"I dare predict that 50 years from now every psychology department will have Darwin's bearded portrait on the wall. Evolutionary approaches have the potential to produce a conceptual framework that will accommodate or replace the proliferation of disconnected theories in the study of human behavior"
de Waal, F. B. M. (2002). Evolutionary Psychology: The Wheat and the Chaff. Current Directions in Psychological Science, 11(6), 187-191. https://doi.org/10.1111/1467-8721.00197
We are not there yet, but I can see the Grand Old Man already smiling.