Even the most outgoing, extroverted person needs some alone time. Because socializing is exhausting – for our brain. That’s the conclusion of new research from the University of Helsinki. They found that the more social people were, the more they reported being in a positive mood and feeling lower levels of fatigue. But those effects wore off at the 3-hour mark. After that, people who were still interacting with a group saw their mood drop and their fatigue increase. And that was true for social butterflies AND introverts. That’s because socializing is really taxing on the brain. Conversations, processing language, activating your memory, and reading body language use up a lot of mental energy. And for anyone, talking to a bunch of people for a long time – specifically 3-hours – is draining. So maybe we should all make sure our parties are only 3-hours long.