You spend years trying to learn new stuff but then look back and realize that maybe like 10 big ideas truly changed how you think and drive most of what you believe.

Brent Beshore recently listed the biggest ideas that changed his life. A few of mine:

Everyone belongs to a tribe and underestimates how influential that tribe is on their thinking. There is little correlation between climate change denial and scientific literacy. But there is a strong correlation between climate change denial and political affiliation. That’s an extreme example, but everyone has views persuaded by identity over pure analysis. There’s four parts to this:

• Tribes are everywhere: Countries, states, parties, companies, industries, departments, investment styles, economic philosophies, religions, families, schools, majors, credentials, Twitter communities.

• People are drawn to tribes because there’s comfort in knowing others understand your background and goals.

• Tribes reduce the ability to challenge ideas or diversify your views because no one wants to lose support of the tribe.

• Tribes are as self-interested as people, encouraging ideas and narratives that promote their survival. But they’re exponentially more influential than any single person. So tribes are very effective at promoting views that aren’t analytical or rational, and people loyal to their tribes are very poor at realizing it.

Psychologist Geoffrey Cohen once showed Democratic voters supported Republican proposals when they were attributed to fellow Democrats more than they supported Democratic proposals attributed to Republicans (and the opposite for Republican voters). This kind of stuff happens everywhere, in every field, if you look for it.

Everything’s been done before. The scenes change but the behaviors and outcomes don’t. Historian Niall Ferguson’s plug for his profession is that “The dead outnumber the living 14 to 1, and we ignore the accumulated experience of such a huge majority of mankind at our peril.” The biggest lesson from the 100 billion people who are no longer alive is that they tried everything we’re trying today. The details were different, but they tried to outwit entrenched competition. They swung from optimism to pessimism at the worst times. They battled unsuccessfully against reversion to the mean. They learned that popular things seem safe because so many people are involved, but they’re most dangerous because they’re most competitive. Same stuff that guides today, and will guide tomorrow. History is abused when specific events are used as a guide to the future. It’s way more useful as a benchmark for how people react to risk and incentives, which is pretty stable over time.

Multi-discipline learning: There’s as much to learn about your field from other fields than there is within your field. Most professions, even ones that look wildly different, live under the umbrella of “Understanding how people respond to incentives, how to convincingly solve their problems, and how to work with others who are difficult to communicate with and/or disagree with you.” Once you see the roots shared by most fields you realize there’s a sink of information you’ve been ignoring that can help you make better sense of your own profession. I didn’t appreciate how important communication is to providing investment advice before reading about how many doctors struggle to communicate effectively with patients, leading to patients who don’t stick with treatment plans and are resistant to lifestyle change. There are millions of these dots to connect. Probing beyond the confines of your day job is more fun anyways.

Self-interest can lead people to believe and justify nearly anything. Think about businesses trying to survive competition being run by people trying to prove their career worth, and the incentive to run with the option that provides the cleanest path to the next win is huge, even when that option is something you wouldn’t accept in less-stressful circumstances. I have seen investors justify strategies and sales techniques they fiercely argued against at previous employers, coming around the moment their career depended on it. These are good, honest people. But self-interest is a freight train of persuasion. When you accept how powerful it is you become more skeptical of promotion, and more empathetic to those doing the promoting.

Room for error is underappreciated and misunderstood. It’s usually viewed as a conservative hedge, used by those who don’t want to take much risk. But when used appropriately it’s the opposite. Room for error lets you stick around long enough to let the odds of benefiting from a low-probability outcome fall in your favor. Since the biggest gains occur the most infrequently – either because they don’t happen often or because they take time to compound – the person with enough room for error in part of their strategy to let them endure hardship in the other part of their strategy has an edge over the person who gets wiped out, game over, insert more tokens, at the first hiccup.

Sustainable sources of competitive advantage. This might be the most important topic in business and investing because other than luck it is the only path to long-term success. The only truly sustainable sources of competitive advantage I know of are:

• Learn faster than your competition.

• Empathize with customers more than your competition.

• Communicate more effectively than your competition.

• Be willing to fail more than your competition.

• Wait longer than your competition.

Everything else – intelligence, design, insight – gets smashed to pieces by competitors who are almost certainly as smart as you.

Your personal experiences make up maybe 0.00000001% of what’s happened in the world but maybe 80% of how you think the world works. People believe what they’ve seen happen exponentially more than what they read about has happened to other people, if they read about other people at all. We’re all biased to our own personal history. Everyone. If you’ve lived through hyperinflation, or a 50% bear market, or were born to rich parents, or have been discriminated against, you both understand something that people who haven’t experienced those things never will, but you’ll also likely overestimate the prevalence of those things happening again, or happening to other people.

Start with the assumption that everyone is innocently out of touch and you’ll be more likely to explore what’s going on through multiple points of view, instead of cramming what’s going on into the framework of your own experiences. It’s hard to do. It’s uncomfortable when you do. But it’s the only way to get closer to figuring out why people behave like they do