It's not often that a toothbrush unlocks an epiphany about company culture--but that's exactly what happened to famed investor and entrepreneur Ben Horowitz.

Speaking at the 2019 Fast Company Innovation Festival in New York City on Tuesday, the Andreessen Horowitz co-founder talked about how a chance encounter with author and prison reform activist Shaka Senghor--who joined Horowitz onstage for the event--led to the realization that prompted his new book, What You Do Is Who You Are: How to Create Your Business Culture.

As Horowitz recounted, it started with a simple question: If someone stole your toothbrush, how would you respond? In prison, Senghor told Horowitz, that's a litmus test. If you do nothing, you'll be seen as an easy mark for the remainder of your prison term. If you overreact and kill the thief, you'll set a lasting tone of extreme violence. The anecdote redefined culture for Horowitz: It's not just your words and actions, he said, but how people behave based on them.

Beginning in 1991, Senghor spent 19 years in Michigan prisons after being convicted of second-degree murder. He described his first day in prison as an adjustment to a significantly higher level of violence than he'd experienced before his conviction. Horowitz drew a parallel to the business world, noting that while the stakes aren't as high, every new job's Day 1 also involves scoping out the office's power dynamics. "You're looking at who's successful," he said. "Oh, that person's got the big job and just took credit for that other person's work? That's how you succeed here. And that sets the culture much more so than anything you're going to say at an all-hands."

The parallels continue all the way through the corporate experience, Horowitz added. In this era of transient workforces, employees rarely stay in one place for decades--much like prison's inherent personnel churn. That should force leaders to reconsider their workplace's most important elements, especially if they want to retain top performers. And in Horowitz's experience, money is no longer the predominant driver for most employees. It's time.

"Most of their waking hours are spent with you in this organization," he said, adding that it consequently falls upon the workplace to shape an employee's experience. "As a leader, that's the biggest thing that you do. I don't care if they're there for a week or 10 years."