Ben Horowitz's What You Do Is Who You Are revolves around signalling.

The problem is culture. The setting is in the hallways and offices of billion dollar businesses and nascent startups. The audience is CEOs and managers. The main characters, Toussaint Louverture, Genghis Kahn, and Shaka Seghor are from different worlds. But the fundamental principle comes from economic theory.

Signalling is about credibly communicating a message by paying the adequate cost. The idea is used in biology and economics to explain everything from the plumage in a peacock's tail to healthcare consumption habits. The idea is simple. Suppose I want to convince you that I'm a devout member of your religious group. I could say that I am. But that wouldn't be very convincing, talk is cheap. So, what I do is attend religious services, wear the appropriate attire, stay away from alcohol, and memorize religious texts. Each of these activities carry costs and the fact that I'm willing to pay them is evidence that I'm devout.

What you do is who you are is another way of saying that you aren't who you say you are. Talk is cheap. A company isn't a list of values or its vision, but what it does. A person isn't the values they profess, but what they reveal through behavior.

Toussaint Louverture was the military general responsible for liberating Haiti from France. Clearly a genius, he was distinctive for being admired by both Haitians and many of the French. There are a few lessons to take from his life. Toussaint Louverture needed to build trust in a low trust culture. Amongst other things, he made an unusual rule forbidding married officers from having concubines:

“Because in this army, nothing is more important than your word. If we can’t trust you to keep your word to your wife, we definitely can’t trust you to keep your word to us.”

This created a standard for enforcing trust. Horowitz calls this heuristic: create shocking rules. A rule is shocking when it specifies something to be given up. If a rule isn't shocking then it risks not being taking seriously. If living according to your principles doesn't cost you anything, it may not be that much signal.

Another heuristic: dress for success. Dressing well communicates many things, but one thing it can make clear is how how high standards are. Outmaneuver and outdress!

Another heuristic: make decisions that demonstrate cultural priorities. Louverture didn't just let French plantation owners live, he let them keep their land:

With these decisions, Louverture established what a thousand speeches could not have: that the revolution wasn’t about revenge and that the economic well-being of the colony was its highest priority. It was all very well for him to say “no reprisals,” but it was what he did that set the culture.

Note that this was not a popular policy. His successor, Jean-Jacques Dessalines, overturned it and contributed to the economic downfall of Haiti.

Yet another heuristic: walk the talk.  In order to show that you're genuine you need to put yourself and what you value on the line.

Louverture understood this perfectly. He asked a great deal from his soldiers, but he was more than willing to embody his own standards. He lived with the men in his army and shared their labors. If a cannon had to be moved, he pitched in, once getting a hand badly crushed in the process. He charged at his troops’ head, something Europe had rarely seen from a leader since Alexander the Great, and was wounded seventeen times.

A slogan spin on this is that you need to demand high standards for yourself, before you demand them from someone else. Ben Horowitz cites the following saying from the army:

There’s a saying in the military that if you see something below standard and do nothing, then you’ve set a new standard. This is also true of culture—if you see something off-culture and ignore it, you’ve created a new culture.

The final heuristic: make the ethics explicit. Louverture was sensitive to the "fate which has befallen some unhappy whites who have been victims in this business." He'd show that this was so by giving food away to destitute local whites, despite having his own starving army to feed.

Each of these rules are variations on a theme. Louverture wanted a high-trust, high-performing army and eventual reconciliation with the French colonialists. In order to get that, he had to pay non-trivial costs, in other words genuinely signal their value to him and others.

Horowitz is at his best when he's laying out difficult scenarios and decisions that people need to make (see The Hard Thing About Hard Things). If signalling is the first theme of the book then the second theme is that it's difficult to know how to shape culture and what to shape it into. You need to do the hard work of reasoning through it. Likely the best part of the book are records of conversations between Ben Horowitz and startup CEOs: one get's a sense of how this reasoning is done. See the chapter, Edge Cases and Object Lessons.

But here's an example from Shaka Seghor. Shaka was imprisoned early in his life and spent 19 years in the system. He gives the case of an outsider stealing one of his men's toothbrushes. What do you do? Ben Horowitz's initial take is let it slide. Shaka responds:

He corrected me: “A guy doesn’t take that risk for clean teeth. It’s a diagnostic. If we don’t respond, then he knows he can rob your guy of something larger or rape him or kill him and take over his business. So if I do nothing, I put all our members at risk. Killing the guy would be a big deterrent—but it would also create a superviolent culture.” He spread his hands. “As I said, it’s complex.”

So you rough the guy up. Maybe.

The squad can go further and cement their status as unexploitable by wiping out the aggressor. Now what do you do if one of your members stole the toothbrush and you hear that the other squad wants to rough him up? If you're too aggressive, you'll be tempted to launch a pre-emptive strike, but:

If you handle external matters this way, people in your organization will look at that as a model. If you don’t, then the way you treat outsiders will leak back into your own organization.

The implicit model of signalling from Toussaint Louverture largely concerned what he was communicating to the Haitian army. The need to have high standards, trust, and ability to reconcile. The story is more complicated. Here, Shaka Seghor needs to make decisions that communicate messages to both his men and opposing squads. If he's not aggressive enough, that risks looking soft to his own men and exploitable to other groups. If he's too aggressive, he's building a culture of might makes right. Not only that, but you want to ensure that the values you're creating are the one's you want long term. By solving one problem, you may not like who you and your organization become in the process. These issues are hard, but not insurmountable - so long as you aren't expecting Plato's Republic.

The book is as much self help as it is business strategy. At the end of the book, Ben Horowitz offers a number of strategies that can be rewritten as heuristics for individuals:

  • Align your culture with your personality and actions: what you communicate, what you do, and who you are should be aligned.
  • Cultural orientation for employees is essential: first impressions matter.
  • Rules need to be shocking in order to work: values should specify what is being given up.
  • Incorporate outside leadership: seek and listen to feedback.
  • Object lessons: if you need to cement a lesson, make it dramatic.
  • Make decisions that demonstrate cultural priorities: someone should be able to read off your values from your actions.
  • Make the ethics explicit: every statement you utter should be understood.
  • Walk the talk.