Thursday, June 11, 2015

How we really make decisions

There were two stories in the news today that are great demonstrations of how our brains really make decisions, even though it doesn’t feel that way to us when it is actually happening.

Big Papi

In the first story, Red Sox slugger David Ortiz got benched against left-handed pitcher Wei-Yin Chen.  If you know Big Papi, you would know that he was NOT happy about this. The manager pointed to Papi’s recent struggles against lefties.  There are a variety of stats that could have been used: his season average overall, his season against lefties, his recent stats overall (because baseball players are streaky hitters), his recent stats against lefties, his stats against this pitcher in past games.

Here are two possible ways the decision could be made.

1. The “rational” decision would be to weight each of the stats by how well they predict how Papi will do. Then plug in his stats and see if he is better or worse than the player who would replace him.  This is called multi-attribute utility analysis (MAUA).
2. The faster “rational” decision (if speed were necessary, as it often is) would be to select the stat that is the most diagnostic and rely on that one. This is called lexicographic analysis.
3. The reality – the manager’s instinct would push him towards one option based on which ones gives him a better feeling (or the least bad feeling).  Then while he is looking at the stats his unconscious would find the ones that support his decision and compose a story that justifies what his instinct had already decided.  For each person he needs to convince, a slightly different story would emerge because these are created in real time and based in part on who he is talking to – Papi, the news media, etc.

Malaysian earthquake 

In the second story, a minister in the Malaysian government attributed the major earthquake earlier this year to the fact that a few tourists had stripped naked on top of the volcano Mount Kinabalu, offending the mountain spirits that reside there.

This might just sound silly, but it is pretty similar.  It is not about whether this is diagnostic evidence.  His instinct told him that someone had to be at fault. There was too much heartbreak not to default to blaming someone.  Blaming international tourists, especially from the West, offers the least pain and perhaps a little righteous, indignant anger.

And the story is a good one, compelling for anyone who might believe it.