According to a recent study in the Proceedings of the National Academy of Sciences, researchers at University College London have developed a mathematical formula that successfully predicted the happiness of more than 18,000 people.

To develop the formula, the neural activity of 26 subjects was examined as they made decisions that would affect monetary gain or loss. As they made decisions, they were repeatedly asked the question, "How happy are you right now?" Interestingly, wealth amassed during the study did not increase people's happiness. The recent history of rewards and expectations was a much more accurate predictor.

The formula was then tested by 18,000+ worldwide volunteers who participated using a smartphone app called The Great Brain Experiment.

Until now, much research into happiness looked at the life events that a person experiences. But this new equation is meant to predict happiness in the moment as a person makes decisions and gets feedback about the outcome of those decisions. It shows that moment-to-moment happiness is strongly associated with how well a decision works compared to a person's expectation about how well the decision would work.

What the Experts Say

“An equation that shows what leads to happiness is interesting,” says Victor Fornari, MD, chief of child and adolescent psychiatry at LIJ Medical Center. “When we talk about a formula for happiness, we are trying to understand what it is that gives people a sense of fulfillment and inner calm, a sense of gratification.”

The study suggests that there might be truth in the idea that lowering your expectations may lead to more happiness. “If you set your goals unrealistically high, you set yourself up for failure, which is demoralizing,” Fornari says.

According to Deb Carlin, MS, Ph.D, the author of the forthcoming book, Build the Strength Within: Create the Blueprint for Your Best Life Yet, expectations are definitely linked to happiness. “The researchers who came up with the equation were surprised at just how important expectations are when determining happiness,” Carlin says. “People have a tendency to set themselves up unrealistically and then be disappointed. People need to tune into themselves more and to set realistic goals."

Carlin points out that the study also noted that happiness does change moment to moment. “You can train your brain so that you are in touch with your thoughts and your feelings,” she says. “But you need to sit down and tune in to these feelings. There’s brain activity that is involved here. Each one of us is the producer, director, actor, and scriptwriter of our own brain activities.”

While wealth does not appear to increase happiness, being kind to others and sharing does. “People simply feel good when they share,” Carlin says. “It is a positive experience that leads to a sense of well-being.”

Redefining the word ‘happiness’ so that it actually means ‘having peace with your purpose’ is helpful, too, says Stephanie Adams, MA, LPC, a counselor in Dallas, Texas and a member of the American Counseling Association. “Being happy is about finding a purpose and living with that purpose. When you recognize a goal that has value to you and you are fulfilling that goal, this brings about personal satisfaction.”

Curious about The Great Brain Experiment? Learn how you can participate at

Deb Carlin, MS, Ph.D., reviewed this article.


Robb B. Rutledge, Nikolina Skandali, Peter Dayan, and Raymond J. Dolan.“A Computational and Neural Model of Momentary Subjective Well-Being.” Proceedings of the National Academy of Sciences, 2014 DOI: 10.1073/pnas.1407535111

University College London. "Mathematical Equation to Predict Happiness: Doesn't Depend on How Well Things Go, But on Whether Things Are Better Than Expected." Science Daily. August 4, 2014.

Stephanie Adams, MA, LPC. Email interview with source. August 2015.

Deb Carlin, MS, Ph.D. Email interview with source. August 2015.