Today’s post is by Robb Rutledge, Max Planck University College London Centre for Computational Psychiatry and Ageing Research
What makes us happy? Well-being researchers have identified many variables related to happiness, but we still don’t know exactly how the events of our daily lives combine to influence how we feel from moment to moment. People should get happier when good things happen, but clearly this is not the whole story.
We designed a study to investigate the relationship between rewards and happiness. We brought people into the lab and asked them repeatedly about their happiness as they chose between safe and risky monetary options. Risky choices were gambles with equal probabilities (like a coin toss) of a better or worse outcome. If they chose to gamble on a given trial, they then found out whether they won or lost. Based on the data, we developed a mathematical equation to predict how self-reported happiness depends on past events. We found that happiness depends not on how well things are going, but whether things are going better or worse than expected.
Happiness depends on safe choices (certain rewards, CR), expectations associated with risky choices (expected value, EV), and whether the outcomes of risky choices were better or worse than expected. This final variable is called a reward prediction error (RPE), the difference between the experienced outcome and the expectation. The neurotransmitter dopamine is thought to represent these signals which might explain how people learn about rewards (if you get more than you expected, next time you should expect more).
How do our findings translate to real life? As soon as you make a plan to meet a friend for dinner, your happiness should increase in anticipation. If you manage to get a last-minute reservation at a popular new restaurant, your happiness might increase even more. If the meal is good, but not quite as good as expected, your happiness should actually decrease. Our equation predicts exactly how much happiness will go up and down, and our results reveal just how important expectations are.
Happiness is a difficult thing to measure, and one concern is that something about being in the lab is important for our findings. Working with a team of researchers at University College London, we developed a smartphone app called the Great Brain Experiment. The app is free and available in the Apple and Android app stores. We invite everyone to download the app and to play the different games. By playing the games, you contribute to ongoing research on important questions in psychology and neuroscience. In the game ‘What makes me happy?’ players choose between safe and risky options to win as many points as they can.
Using our mathematical equation, we could predict the happiness of over 18 000 people worldwide playing our game. Our results demonstrate that something as complicated as happiness can be studied using smartphones. As more people play the game, we can start to look for differences between groups, like players of different ages and cultures.
To better understand the link between rewards and happiness, we also had people play our game while having their brains scanned. We found that neural activity in an area of the brain called the striatum was closely related to reported happiness. When activity was high, we could predict that happiness would increase. Because this area has many connections to dopamine neurons, one interesting possibility is that dopamine levels help determine happiness. Our equation provides predictions that we can use to study the neural circuits involved in happiness. We can ask questions like whether factors that matter for happiness in young people differ in an important way from happiness in adults. The equation also gives us a tool for identifying differences between people that may help us better understand mood disorders like major depression.
As a researcher studying happiness, people often ask me how they can be happier. Our equation might make it seem like low expectations are the secret to happiness, but that’s not the case. Low expectations do make it more likely that an outcome will exceed expectations and positively impact happiness, but expectations also affect happiness before we find out how a decision turned out. We often don’t know the outcome of major life decisions for a long time, whether taking a new job or getting married, but our results suggest that positive expectations about those decisions will increase happiness. In general, accurate expectations may be best. Our expectations help us decide where to go for dinner and tell us whether a new restaurant is as good as everyone says it is. Although we all want to be happy, being happy all of the time is probably not a good idea. If you were ecstatic after every meal, you would never be able to decide which restaurant to go to. Our happiness tells us whether things are going better or worse than expected, and that may be a very useful signal for helping us make decisions.
Low expectations may not be the secret to happiness, but being able to predict happiness based on past rewards and expectations bring us one step closer to understanding happiness. By studying how happiness depends on the interaction between our brains and our environment, we hope to yield insights that contribute to the important goal of improving human well-being.
These findings were reported in R. B. Rutledge, N. Skandali, P. Dayan & R. J. Dolan (2014) “A computational and neural model of momentary subjective well-being” Proceedings of the National Academy of Sciences USA (PNAS). Vol. 111, No. 33, pp. 12252-12257.