More positive people are better able to learn new things; consider this:

If you can raise somebody’s level of positivity in the present, then their brain experiences what we now call a happiness advantage, which is your brain at positive performs significantly better than it does at negative, neutral or stressed. Your intelligence rises, your creativity rises, your energy levels rise. In fact, what we’ve found is that every single business outcome improves. Your brain at positive is 31 percent more productive than your brain at negative, neutral or stressed.You’re 37 percent better at sales. Doctors are 19 percent faster, more accurate at coming up with the correct diagnosis when positive instead of negative, neutral or stressed. Which means we can reverse the formula. If we can find a way of becoming positive in the present,then our brains work even more successfully as we’re able to work harder, faster and more intelligently.

How? 

In just a two-minute span of time done for 21 days in a row, we can actually rewire your brain, allowing your brain to actually work more optimistically and more successfully. And at the end of that, their brain starts to retain a pattern of scanning the world, not for the negative, but for the positive first.

“[W]rite down three new things that they’re grateful for for 21 days in a row, three new things each day. And at the end of that, their brain starts to retain a pattern of scanning the world, not for the negative, but for the positive first.”

“Journaling about one positive experience you’ve had over the past 24 hours allows your brain to relive it.

We find that meditation allows your brain to get over the cultural ADHD that we’ve been creating by trying to do multiple tasks at once and allows our brains to focus on the task at hand.

“[R]andom acts of kindness are conscious acts of kindness. We get people, when they open up their inbox, to write one positive email praising or thanking somebody in their social support network.

Shawn Achor: The happy secret to better work | Video on TED.com.