The Mathematics of Happiness

By Jane Farrell

Scientists have developed a mathematical model to measure happiness, and that may eventually lead to better treatments for mood disorders.

Researchers from University College London used the equation to analyze the happiness of more than 18,000 people worldwide. As a result, they found that moment-by-moment happiness is due not only to how well things are going but whether they are going better than a person expected.

The study was published in the Proceedings of the National Academy of Sciences.
Until now there’s been no analysis of how happy a person can be as he or she makes decisions and gets results stemming from those decisions. The new equation can predict this.

The researchers said that concrete measurements of subjective states could help physicians better understand mood disorders such as depression.

In the study, 26 people completed a task in which their choices led to financial gains and losses. They were repeatedly asked how happy they were “right now” as they moved through the process. The investigators measured the person’s brain activity using MRIs and built a computer model in which happiness was related to rewards and expectations.

The model was then used in a test on 18,240 participants in a game called What Makes Me Happy? The game was part of a smartphone app developed at the University.

Researchers found that the statistics from the first survey could accurate predict a subject’s happiness while using the smartphone app.

The study’s lead author, Dr. Robb Rutledge, said the researchers were surprised to find out how important expectations were in determining happiness.

Rutledge said that life “is full of expectations – it would be difficult to make good decisions without knowing, for example, which restaurant you like better. However, expectations also affect happiness even before we learn the outcome of a decision. If you have plans to meet a friend at your favorite restaurant, those positive expectations may increase your happiness as soon as you make the plan. The new equation captures these different effects of expectations and allows happiness to be predicted based on the combined effects of many past events.”