Algorithms to Live By Summary

Algorithms to Live By offers shortcuts and hacks to help streamline your life. Algorithms are inserted into computers and other forms of technology to solve problems. However, there is no reason that we cannot use algorithms in our everyday lives. Brian Christian and Tom Griffiths describe how algorithms have been used for centuries. Plus, how we use specific algorithms daily. However, some algorithms are more efficient than others. This book provides an outline of the algorithms that can help make your life easier and more enjoyable. 

When you are hiring, scouting houses to buy, options to consider — when should you stop looking?

You stop looking too early, you don’t know if someone better isn’t going to come along. You stop too late, you might have passed on the best candidate already.

Mathematically — you should stop looking after evaluating 37% of all the options you’re willing to look at. After the 37% option — if anything/anyone comes along who is better than everyone else before you should make the decision.

When should you be exploring new options and when should you start settling for the best option you already know? Consider these concepts: 

• Regret Minimisation Framework: When you look back on your life when you’re 80, what will you regret least?
• Exploring: In decision making, we consider the single highest pay-off on our single decision, but in the long term, it’s way more efficient to first explore your options, before exploiting the highest pay-off decision.
• Ageing: Deepest insight about later life is that you can exploit knowledge acquired over decades — life should get better over time.

The Optimal Stopping Problem provides a mathematical solution to when to stop looking and decide. The 37% Rule works like this:

• Determine how many options you'll likely encounter (n)

• Look at the first 37% of options (n/e, where e is Euler's number)

• Remember the best option seen so far, but don't choose any

• After the 37% mark, select the first option better than all previous ones

This approach guarantees finding the best option 37% of the time—mathematically proven to be the best possible success rate. Applications include hiring, dating, apartment hunting, and any sequence of irreversible decisions.

The Explore/Exploit Tradeoff represents a fundamental tension in decision-making: trying new things or sticking with known rewards. This framework reveals:

• Early in any timeline, exploration delivers more long-term value

• As time horizon shortens, exploitation becomes optimal

• The mathematical solution is the Gittins index, which assigns values to each option

• Our intuitions often align with this model—we explore more when young and exploit more as we age

This explains why children explore constantly while elderly people stick with favorites. The optimal strategy depends on how much time remains for using the information gained.