This Is the Equation for Happiness

Researchers at University College London were able to create an equation that could accurately predict the happiness of over 18,000 people, according to a new study.

First, the researchers had 26 participants complete decisionmaking tasks in which their choices either led to monetary gains or losses. The researchers used fMRI imaging to measure their brain activity, and asked them repeatedly, “How happy are you now?” Based on the data the researchers gathered from the first experiment, they created a model that linked self-reported happiness to recent rewards and expectations.

Here’s what the equation looks like:

Then, in their study published Monday in the Proceedings of the National Academy of Sciences, the researchers tested their model by having 18,420 people play a smartphone game called The Great Brain Experiment for points. They found that their equation was also accurate at predicting the gamers’ happiness.

The researchers were not surprised by how much rewards influenced happiness, but they were surprised by how much expectations could. The researchers say their findings do support the theory that if you have low expectations, you can never be disappointed, but they also found that the positive expectations you have for something—like going to your favorite restaurant with a friend—is a large part of what develops your happiness.

The fact that the researchers could accurately predict happiness was notable, but the implications are even better. Having a predictable standard for how people respond to moment-to-moment gains and losses could actually make mood disorders easier to understand by learning how someone with a mood disorder differs in their reactions to events.