One of the clearest signs of learning is rethinking your assumptions and revising your opinions. 21 things I rethought in 2021: a thread...

Learning a second language can protect against cognitive decline. Data from 86k people across 27 countries: Being multilingual predicted 30% lower risk of accelerated biological aging over time. Communicating in multiple tongues is a form of mental exercise.

Helicopter parenting has reached a new low: Some parents are following their kids to campus. College is a time for gaining independence, not having parents hovering nearby in case they're "needed". When we fail to respect their autonomy, kids fail to learn responsibility.

Even when women are the primary breadwinners, they do more housework than men. Wives who outearn husbands still do twice the cooking & cleaning. Men who earn 20% vs. 80% of household income do similarly small amounts of housework. Roles should be divided by equity, not gender.

It's time to remove laptops from classrooms. 24 experiments: Students learn more and get better grades after taking notes by hand than typing. It's not just because they're less distracted—writing enables deeper processing and more images. The pen is mightier than the keyboard.

Women aren't only underpaid because they end up in less lucrative careers than men. Data on >25M people across 15 countries: Women make less than men in the same job—and that accounts for about half the overall gender pay gap. Equal work deserves equal pay. Full stop.

Bingeing TikTok reels may be hazardous to your well-being. 71 studies, >98k people: The more short-form videos teens and adults watched, the more they struggled with attention, self-control, and stress and anxiety. Read a book. Watch a movie. Long live longform.

One of our most important career decisions is who we marry. People earn more—and are happier—if their spouses are dependable and hardworking. Conscientious partners give more support and model better habits. We don't only benefit from our loved ones' strengths; we absorb them.

We judge people too much by their fleeting opinions—and too little by their consistent actions. Anyone you meet is likely to hold some views you dislike. No one is as bad as their worst idea, and no belief is set in stone. The true test of character is how people treat others.

Too many mediocre men talk over capable women. Study of problem-solving teams: Men dominate the conversation, taking 50% more turns and saying 69% more than women. Men with low skill speak more than women with high skill. It's long past time to value competence over confidence.

Phone bans in schools motivate kids to read. When a Kentucky district eliminated phones, students checked out 2.3x as many books from the library. At one school, twice as many students borrowed books in the first month as all of last year. Without smartphones, kids get smarter.

The more girls in a class, the merrier. Data on 87k students: In cohorts with more girls, boys and girls have better mental health. More female peers predicts closer friendships for boys—and better body image & STEM grades for girls. Girls build cultures of competence and care.

Cursing is rarely a symbol of low class. It's often a mark of high authenticity. Evidence: Swearing predicts higher rates of honesty and integrity. It signals a willingness to prize candor over courtesy. A little profanity shows that you're being real and you do give a damn.

If you reach your goals by compromising your values, you haven’t succeeded. If you fall short of your goals by upholding your values, you haven’t failed. The true measure of accomplishment is standing by your principles when they’re tested.

When you get defensive about feedback, you fail twice. You fail to learn today, and you fail to encourage people to keep teaching you tomorrow. If you can't handle the truth, people stop telling you the truth. A key to growth is showing that you're coachable.

Daily connection builds a healthier worldview. Data: When people have regular positive interactions with others who matter to them, they see the world as a better place a year later—and have lower depression and higher well-being. Strong ties are an antidote to alienation.

Men become more caring when they become girldads. Data on >12k CEOs: After having a firstborn daughter, men spend 10% more on social responsibility initiatives—especially culture, inclusion, and the environment. They also pay female employees better. Daughters activate empathy.

We spend too much time arguing like we're right—and too little time listening like we're wrong. Diatribes don't change minds. Productive disagreement depends on showing respect, curiosity, and humility. The most compelling teachers are the ones who are most eager to learn.

Another nail in the astrology coffin: 152 astrologers did no better than random chance at guessing people’s charts from detailed info about them. Astrologers helped design the test, and "experts" failed at the same rate as novices. Horoscopes may be fun, but they ain't real.

Forcing people back to the office backfires. Data on >3M tech & finance workers: After return-to-office mandates, firms lose stars and struggle to attract new talent. The most likely to quit are senior, skilled, & female employees. Flexibility is a feature of a great workplace.

A mark of emotional intelligence is prioritizing your values over your moods. Immature people are victims of their feelings. Their choices are governed by fleeting sensations. Mature people take responsibility for their reactions. Their choices are guided by lasting principles.