The past three trading days have been a roller-coaster ride for global markets.At this morning's opening bell on Wall Street, the Dow Jones industrial average plunged more than 500 points,and then ended the trading day up more than 500 points, a 1,000-point swing.To help us understand this, we are joined by Neil Irwin, senior economics correspondent for The New York Times' Upshot.Neil, thanks for being here. This morning, you wrote that the key to keep in mind is to keep the long view in mind.So, having said that, what do we take from the last three days?Well, I think the era of extreme low volatility may be over, at least for a while.I think it might come back, but for now this period we had, all of 2017, not a single day of the stock market losing more than 2 percent.That's very unusual. And we have now had two of those days out of the last three trading sessions.This is clearly a more volatile environment. This is clearly a time when stocks are going crazy.That said, we're still only at about mid-December levels. We're down only a little bit for the year.We haven't even hit the correction level of losing 10 percent in stock value. So, this isn't a crisis.This isn't something to worry about too much. At the same time, it's certainly is a little teeth-chattering when you watch the daily stock market ticker.And, in a way, it was a return of volatility. We hadn't seen this sort of volatility in quite a while.Why do you think it came back this way?There seems to be some self-fulfilling cycles happening. There are a lot of investors betting against volatility.There is also some news behind this. There was a jobs report Friday that suggested wage growth is a little stronger than it appeared.