Echolocation in Humans, Altruism in Dogs, and Mental-Health Outcomes of Gender Reassignment

The Nature-Nurture-Nietzsche Linkfest for April 2026

Apr 28, 2026

∙ Paid

grayscale photo of girl in sweater holding dogs face — Photo by mali desha on Unsplash

In Case You Missed It…

Welcome to the April 2026 edition of the N³ Newsletter Linkfest: a collection of links to papers and articles that grabbed my attention over the last month. On the menu today…

An innate sense of kindness in humans and dogs
Why greater gender equality means fewer babies
Three new findings on personality, three new findings on sex differences, and three new findings on gender issues
The lengths females go to to avoid unwanted male attention
The downside of reclaiming slurs
And we’ll ask: Which is more common, misogyny or misandry? Does gender reassignment help or harm the mental health of youth with gender dysphoria? And does DEI foster inclusion and mutual understanding or division and hostility?

The first half of the Linkfest is free to read for everyone; the rest is for paid subscribers. I tend to put my spicier content behind a paywall, so if you want a taste of that, consider becoming a paid subscriber.

You can read about the benefits of a paid subscription here, and you can access the complete collection of Linkfests here.

But First, Some News…

I’ll be appearing at the How the Light Gets In festival in Hay-on-Wye this May 22-25, doing a debate about the merits and demerits of spirituality, a podcast with Michael Shermer, and an event for my forthcoming book A Billion Years of Sex Differences.

Wanna come? You should come; it’ll be fun!

Explore tickets

Echolocation in Humans

Some blind people don’t just learn to live without vision; they replace it with something arguably just as impressive: echolocation. Specifically, they make click sounds with their mouths, then use the returning echoes to detect objects and navigate through the world. In a clever EEG study, blind echolocators outperformed sighted participants at locating objects in the dark, progressively refining their spatial judgments by integrating echoes across multiple clicks. [Link.]

Born to Give

Toddlers, it turns out, are tiny altruists: They’re happier giving treats away than receiving them. Not only that, but they’re happier when they personally give the treats than when someone else does, and happier when they give them spontaneously than because they were told to. This is suggestive evidence that human altruism is driven by the inbuilt emotional rewards of lending a helping hand. [Link.]

Toddlers were first introduced to a puppet (“meet Monkey”) and then received eight treats (“receive treats”). They then participated in four counterbalanced phases: costly giving (giving one of their own treats to Monkey), non-costly giving (giving a treat provided by the experimenter to Monkey), observe giving (watching the experimenter give a treat to Monkey), and give to self (giving a treat provided by the experimenter to themselves). Source: Tan et al. (2026).

Happiness ratings during different phases of the treat giving game. Black dots indicate average scores and red dots indicate median scores. *p < 0.05, ***p < 0.001. Source: Tan et al. (2026).

Dogs Help, Cats Watch

Dogs are about as helpful as toddlers, but cats look out for number one. In a fascinating recent experiment, a human parent pretended to be looking for a lost object. Around three-quarters of toddlers and dogs tried to help. Most cats, in contrast, sat back unless there was something in it for them. Helpfulness, it seems, comes more naturally to some species than others. [Link.]

Dark green represents subjects displaying prosocial behaviors (showing, giving the object to caregiver). Light green indicates subjects showing behaviors that could be attributed to either stimulus enhancement or prosociality (approaching the object, manipulating it without giving it to caregiver). Source: Csepregi et al. (2026).

More Equality, Fewer Babies

Across countries, greater gender equality is associated with lower fertility. With greater freedom and material wealth, women become less dependent on men, and thus less likely to form pair bonds. Combine this with reliable contraception, and the fertility rate comes crashing down. [Link.]

There is a strong association between the freedoms a nation grants its women and how high its fertility rate is. The Pearson correlation is r ≈ 0.81, while the rank order correlation is r ≈ 0.86, N = 172. *Note:* Data from United Nations (2024) and UNDP (2025). Source: Larsen et al. (2026).

The Missing 5’11” Men

Something strange is happening with self-reported height among men: There aren’t enough 5’11” men, and there are too many 6’0” men. Yet another reason why we can’t take self-report data at face value. [Link.]

r/dataisbeautiful - [OC] Body Height Reported by U.S. Men

The Paradox of Upward Mobility

We tend to assume that people who are born poor and get rich will be more sympathetic to the plight of the poor than those who are born rich and stay rich. But it’s the other way around: Those who start out poor are less sympathetic. [Link.]

A Billion Years of Plate Tectonics

This incredible animation compresses a billion years of plate tectonics into just 40 seconds. We tend to think of land masses as stable - but they’re in constant motion. They just move a lot more slowly than us. [Link.]