Equation predicted happiness of over 18,000 people worldwide

August 4, 2014, University College London
This is the happiness equation, where t is the trial number, w0 is a constant term, other weights w capture the influence of different event types, 0 ≤ γ ≤ 1 is a forgetting factor that makes events in more recent trials more influential than those in earlier trials, CRj is the CR if chosen instead of a gamble on trial j, EVj is the EV of a gamble (average reward for the gamble) if chosen on trial j, and RPEj is the RPE on trial j contingent on choice of the gamble. The RPE is equal to the reward received minus the expectation in that trial EVj. If the CR was chosen, then EVj = 0 and RPEj = 0; if the gamble was chosen, then CRj = 0. The variables in the equation are quantities that the neuromodulator dopamine has been associated with in previous neuroscience studies. Credit: Robb Rutledge, UCL

The happiness of over 18,000 people worldwide has been predicted by a mathematical equation developed by researchers at UCL, with results showing that moment-to-moment happiness reflects not just how well things are going, but whether things are going better than expected.

The new equation accurately predicts exactly how happy people will say they are from moment to moment based on recent events, such as the rewards they receive and the expectations they have during a decision-making task. Scientists found that overall wealth accumulated during the experiment was not a good predictor of happiness. Instead, moment-to-moment happiness depended on the recent history of rewards and expectations. These expectations depended, for example, on whether the available options could lead to good or bad outcomes.

The study, published in the Proceedings of the National Academy of Sciences, investigated the relationship between happiness and , and the neural processes that lead to feelings that are central to our conscious experience, such as happiness. Before now, it was known that life events affect an individual's happiness but not exactly how happy people will be from moment to moment as they make decisions and receive outcomes resulting from those decisions, something the new equation can predict.

Scientists believe that quantifying subjective states mathematically could help doctors better understand mood disorders, by seeing how self-reported feelings fluctuate in response to events like small wins and losses in a smartphone game. A better understanding of how mood is determined by life events and circumstances, and how that differs in people suffering from , will hopefully lead to more effective treatments.

Research examining how and why happiness changes from moment to moment in individuals could also assist governments who deploy population measures of wellbeing to inform policy, by providing quantitative insight into what the collected information means. This is especially relevant to the UK following the launch of the National Wellbeing Programme in 2010 and subsequent annual reports by the Office for National Statistics on 'Measuring National Wellbeing'.

As part of the Great Brain Experiment smartphone app, users are periodically asked how happy they feel. Credit: Robb Rutledge, UCL

For the study, 26 subjects completed a decision-making task in which their choices led to monetary gains and losses, and they were repeatedly asked to answer the question 'how happy are you right now?'. The participant's neural activity was also measured during the task using functional MRI and from these data, scientists built a computational model in which self-reported happiness was related to recent rewards and expectations. The model was then tested on 18,420 participants in the game 'What makes me happy?' in a developed at UCL called 'The Great Brain Experiment'. Scientists were surprised to find that the same equation could be used to predict how happy subjects would be while they played the smartphone game, even though subjects could win only points and not money.

Lead author of the study, Dr Robb Rutledge (UCL Wellcome Trust Centre for Neuroimaging and the new Max Planck UCL Centre for Computational Psychiatry and Ageing), said: "We expected to see that recent rewards would affect moment-to-moment happiness but were surprised to find just how important expectations are in determining happiness. In real-world situations, the rewards associated with life decisions such as starting a new job or getting married are often not realised for a long time, and our results suggest expectations related to these decisions, good and bad, have a big effect on happiness.

"Life is full of expectations - it would be difficult to make good decisions without knowing, for example, which restaurant you like better. It is often said that you will be happier if your expectations are lower. We find that there is some truth to this: lower expectations make it more likely that an outcome will exceed those expectations and have a positive impact on happiness. However, expectations also affect happiness even before we learn the outcome of a decision. If you have plans to meet a friend at your favourite 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.

"It's great that the data from the large and varied population using The Great Brain Experiment smartphone app shows that the same happiness equation applies to thousands people worldwide playing our game, as with our much smaller laboratory-based experiments which demonstrate the tremendous value of this approach for studying human well-being on a large scale."

The team used functional MRI to demonstrate that neural signals during decisions and outcomes in the task in an area of the brain called the striatum can be used to predict changes in moment-to-moment happiness. The striatum has a lot of connections with dopamine neurons, and signals in this brain area are thought to depend at least partially on dopamine. These results raise the possibility that dopamine may play a role in determining .

Explore further: Contrary to expectations, life experiences better use of money than material items

More information: A computational and neural model of momentary subjective well-being, PNAS, www.pnas.org/cgi/doi/10.1073/pnas.1407535111

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1 / 5 (3) Aug 04, 2014
I suppose it would be easier to devise an equation to predict the unhappiness of certain groups based solely on their religion-fueled fertility rate.
Aug 04, 2014
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5 / 5 (1) Aug 04, 2014
What's next, a 'happiness pill'? 'For the study, 26 subjects' Really. They'd probably get more info from people who have (a) bad day(s) at work and predict that they will be happier when they get home...don't need an equation for that!
3 / 5 (2) Aug 05, 2014
For those who did not read the article, the 26 people were used to establish the formula (hypothesis). That was then tested on 18K+ people to gather the actual supporting evidence.

Granted, the researchers would do well to continue this data-gathering on many more varieties of sample populations in order to justify claims about a more universal target population (like all humans).
3 / 5 (2) Aug 05, 2014
What's next, a 'happiness pill'?

There are legit use for such research. E.g. one could use it to optimize game design (or on a more practical level: to optimize teaching/learning approaches .)
1 / 5 (1) Aug 05, 2014
Yes, I admit such research has ramifications but I think you misunderstand my point about 'what's next?' Happiness, like other emotions, are subjective and fickle. However, they are often dynamical because there can be an obvious energy change when one changes into another, fear & rage for example. Such systems, imo, are best handled by Catastrophe Theory.
5 / 5 (2) Aug 05, 2014
Such systems, imo, are best handled by Catastrophe Theory.

The facts of this experiment would say the exact opposite. If it were chaotic then there would be much larger variability with minute shifts of initial conditions. That is not observed here.
4 / 5 (4) Aug 05, 2014
his followers actually did that, and were successful. They all died the most happy men on earth
But faith itself is a gamble isnt it? Your poet required believers to abandon home, family, fortune, forget about tomorrow and follow him. Millions who did so died horrible deaths. I really dont think misery qualifies as happiness, at least not in the real world. But those who sell it could often be found wearing hairshirts and cilices. And nailing each other to crosses for easter.

Here is one such congregation.

-And all without a smidgeon of proof, no evidence whatsoever that any of them went anywhere but into the grave.

This might not be a bad bet (we're all going to die anyway) but for the fact that we now know that none of the bible stories ever happened. This skews the odds considerably.
5 / 5 (1) Aug 07, 2014
I love math very much and I can nearly understand what this equation is about. All the factors seem to be taken into account. I also like a forgetting factor. But I'd like to say about some unpredictable factors, for example some spendings that you've not planned. Just not to be broken in such situations I always use http://northandlo...ns.html. It's an easy and quick way to get extra cash when you need it. It's a short-term loan, to apply for it you need to fill in the application form and confirm your solvency.

You know, that's probably the best written spam I've ever seen.
not rated yet Aug 08, 2014
Such systems, imo, are best handled by Catastrophe Theory.

The facts of this experiment would say the exact opposite. If it were chaotic then there would be much larger variability with minute shifts of initial conditions. That is not observed here.

Is not so that emotions can be chaotic? Crimes of Passion and all that! This experiment might be fine...as far as it goes and imo that isn't very far. Even a camera following some mob can be enough to tip them over the edge. This is surely chaotic!
5 / 5 (1) Aug 10, 2014
I believe the key point is:

"We expected to see that recent rewards would affect moment-to-moment happiness but were surprised to find just how important expectations are in determining happiness."

Intuitively it is would seem that when we are getting what we want, we are happy. Or when our life situation is improving, we are happy. What this research found is that either of these could be true, but if we expected better, we may be unhappy. That is pretty interesting, I think.

If true, one needs to start thinking about one's expectations. Evidently lowering expectations would, all things being equal, improve happiness. But what if lowered expectations leads to worse outcomes? Another study?

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