Think of the big events that came out of nowhere and were so dramatic they captured our attention for days. 9/11, the space shuttle, the Kennedy assassination, Pearl Harbor. If you were there you remember exactly where you were.

All of these were bad news.

Now try to think of a comparable good news event. I can’t. The closest is the Moon landing and the first Moon walk. But it doesn’t fit because it was not a surprise. I can’t think of any unexpected joyful event on the order of the magnitude of these tragedies. On the other hand, it’s easy to imagine such an event. For example, if today it were announced that a cure for cancer has been discovered, then that would qualify. And equally significant turns have come to pass, but they always arrive gradually and we see them coming.

What explains this asymmetry?

1. Incentives. If you are planning something that will shake the Earth, then your incentives to give advance warning depend on whether you are planning something good or bad. Terrorism/assassination: keep it secret. Polio vaccine, public.

2. Morbid curiosity. There is no real asymmetry in the magnitude of good and bad events. We just naturally are drawn to the bad ones and so these are more memorable.

3. What’s good is idiosyncratic, we can all agree what is bad.

I think there is something to the first two but 1 can’t explain natural (ie not ingentionally man-made) disasters/miracles and 2 is too close to assuming the conclusion. I think 3 is just a restatement of the puzzle because the really good things are good for all.

I favor this one, suggested by my brother-in-law.

4 . Excessive optimism. There is no real asymmetry. But the good events appear less dramatic than the bad ones because we generally expect good things to happen. The bad events are a shock to our sense of entitlement.

Two related observations that I can’t help but attribute to #4. First, the asymmetry of movements in the stock market. The big swings that come out of the blue are crashes. The upward movements are part of the trend.

Second, Apollo 13. Like many of the most memorable good news events this was good news because it resolved some pending bad news. (When the stock market sees big upward swings they usually come shortly after the initial drop.)  When our confidence has been shaken, we are in a position to be surprised by good news.

I thank Toni, Tom, and James for the conversation.