Why are extraverts happier?

Numerous personality studies have found the same pattern time and again – extraverts tend to be happier than introverts. But why? A popular theory holds that extraverts are happier because they find fun activities more enjoyable, as if they have a more responsive "pleasure system" in their brains than introverts.

A new investigation puts this idea to the test, and is one of the first to compare introverts' and extraverts' momentary happiness in response to different activities in everyday life.

Wido Oerlemans and Arnold Bakker recruited 1,364 Dutch participants (average age 45; 86 per cent were female) to complete a detailed retrospective record of one or more days. The research used the "Day Reconstruction Method", which involves the participants recalling the previous day's activities in chronological order, who they were with, what they were doing, and how they felt during each activity. In total 5,595 days were examined in this way.

A key finding is that extraverts reported more happiness than introverts during what the researchers defined as effortful "rewarding" activities, such as sports and exercise, and financially rewarding work tasks. In contrast, there was no difference in extraverts' and introverts' happiness during merely low effort, low importance "pleasurable, hedonic" activities, such as watching TV, listening to music, relaxing, and shopping.

The one exception to this pattern was reading – surprisingly perhaps, extraverts appeared to derive more enjoyment from this activity than introverts. Oerlemans and Bakker proposed this could be because reading isn't always just for pleasure, but can also be completed in pursuit of a reward, such as to pass a course.

Based on the broad pattern that extraverts experience more happiness during rewarding activities, but not during pleasurable activities, the researchers suggested that existing theories should be refined. It's not that extraverts have a more responsive pleasure system, but rather that they have a more active and responsive "desire system".

Another strand to this study was that it found extraverts experience a bigger happiness boost (than introverts) when they perform rewarding activities with other people, rather than alone. The results also showed that extraverts spend more time on rewarding activities than introverts, and they tend to have more social contact during their daily activities. All this helps explain why extraverts are happier than introverts (or say they are, at least), but it's not the whole story. Even after controlling statistically for the fact that extraverts spend more time with other people and on rewarding activities, there remained a strong relationship between extraversion and happiness.

"Extraverts, because of their active nature, are more likely to seek and spend more time on rewarding activities," the researchers said. "When they do so, they also experience a higher boost in momentary happiness as compared to their introverted counterparts. This partly explains the direct relationship between extraversion and momentary happiness."

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Oerlemans, W., and Bakker, A. (2014). Why extraverts are happier: A day reconstruction study. Journal of Research in Personality, 50, 11-22 DOI: 10.1016/j.jrp.2014.02.001