Can happiness be reduced to a single mathematical equation? Dr Robb Rutledge, a researcher at the Max Planck University College London Centre for Computational Psychiatry and Ageing Research, thinks so. Here is the equation that he and his colleagues estimated with results obtained from experiments on human subjects:
In words, Dr Cobb and colleagues found that happiness depends on three variables: certainty of rewards (CR), expected value of rewards (EV), and, last but not least, a “a reward prediction error (RPE), the difference between the experienced outcome and the expectation”. The three coefficients of interest (w1, w2, w3) are positive and statistically significant.
RPE has a positive effect on happiness, so it might seem reasonable to conclude that low expectations are the key to happiness. Dr Robb warns us, however, that this is not generally true, because low expectations (i.e. low EVs) themselves have a direct impact on happiness. In any event, “being happy all of the time is probably not a good idea”. This last conclusion is one that I did not expect to hear from a happiness researcher!
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. …. 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. [Emphasis added.]
Robb Rutledge, “Can we predict happiness?“, OECD Insights, 23 April 2015.
HT Mark Thoma.