“There are three things in life, health, money and love” , as the song by Cristina and Los Stop from the 1960s would say. The truth is that many people believe that they would be happier if they had more money thanks to the lottery, a good promotion at work, an unexpected inheritance from a distant relative … at least temporarily. But recent studies suggest that the main factor that makes us happier is not the size of the reward received but how that reward matches expectations.
Thus, that they grant us a 10% salary increase when we expected only 1% will make us feel happier than receiving 10% when we really expected that they would grant us 20%. This difference between an expected reward and an actual reward is called the reward prediction error. Reward prediction errors play a key role in learning. They motivate people to repeat the actions that led to unexpectedly great rewards. But they also allow people to update their beliefs about the world , which is also rewarding in and of itself.
Experiments
Hypothesis: Could it be that reward prediction errors are associated with happiness because they help us understand the world a little better than before?
To test this idea, researchers at University College London (UK), Robb Rutledge and Bastien Blain, designed a task in which the probability of receiving a reward was not related to the size of the reward.
“Many people think they would be happier if they had more money,” says Rutledge. “However, we previously developed an equation for happiness that shows that happiness does not depend on the reward they get, but on whether they are doing better than expected.”
For the study, the experts carried out two experiments on human volunteers. In them, they had to choose which car they believed would win a race. If the car of their own choosing won, they received a reward. If not, they did not receive any awards. Participants knew what the potential prize was before deciding which one to bet on, but could only learn from experience which vehicle was most likely to win the race.
In one scenario, one of the cars seemed to be consistently more likely to win, so participants could learn after a few “races” that choosing precisely that car would increase their chances of winning. The other scenario was more volatile, as the car considered “better”, or faster, changed unexpectedly from time to time.
The researchers, who featured their work in eLife magazine, found that the size of the reward did not affect happiness; rather, participants were happier when they could tell which car was better, even when the size of the reward was low. Similarly, they found that being in a changing environment – the fact that the happiest car suddenly changed – lowered their overall happiness, especially among people with depressive symptoms.
“We found that happiness depends on learning, but surprisingly, it does not depend on reward,” says Blain. “Whether the study participants got small or big rewards, it was not the key factor in their happiness.”
Referencia: Bastien Blain & Robb B. Rutledge. 2020. Momentary subjective well-being depends on learning and not reward. ELife 2021 9: e57977; doi: 10.7554/eLife.57977
