The Evolution of (Mis)Trust

Several years ago, I wrote a post about Paul McCartney's 1983 hit single "Pipes of Peace".  Here is what I said on December 25, 2016:

The setting of the video is the Western Front, 1914 (World War I).  On December 25, 1914, French, German, and British soldiers crawled out of their trenches, crossed "No Man's Land," and joined together to celebrate Christmas.  They exchanged food and souvenirs, sang carols, played football (soccer), and drank a toast to peace.  Christmas brought out the best of humankind on that day.  After several months of grueling, hand-to-hand combat, in the middle of the "War to End All Wars," there was peace.  Men who merely hours earlier were killing one another, joined hands, broke bread together, and enjoyed a few quiet moments on Christmas.  On that Christmas night, the guns were silent, bringing special meaning to the Christmas carol, "Silent Night" that they sang.

For a few hours, enemy combatants who had been shooting at each other for days trusted each other enough to walk out into the open where they were easily exposed to gunfire.  Soon thereafter, they returned to their trenches and would fight again on another day.  An artist commemorated the event for the The Illustrated London News on January 9, 1915:

  

Just imagine the level of mutual trust that the two opposing armies had to have in order to do what they did that Christmas night!  The Russian playwright Anton Chekhov said, "You must trust and believe in people or life becomes impossible."  The American clergyman Frank Crane said, "You may be deceived if you trust too much, but you will live in torment if you don't trust enough."  If both Chekhov and Crane are correct (and I believe that they are speaking the truth here), then why is it so hard to trust one another?  If enemy soldiers staring and pointing their guns at each other across a battlefield can trust each other, even for just one short night, then why do we have such a hard time trusting our colleagues, our leaders, or our institutions?  As I stated in a post a month or so ago (see "If only out of curiosity..."), there has been a precipitous decline in trust in today's society.  What gives?  

As it turns out, there is a biological explanation for society's trust issues.  Len Fisher writes about the branch of economics known as game theory in his wonderful book, Rock, Paper, Scissors: Game Theory in Everyday Life.  He dedicated an entire chapter to the concept of "trust" specifically as it related to cooperation versus competition in groups.  Humans are hardwired not to trust each other from an evolutionary standpoint.  It's in our DNA, so to speak.

There is a vast body of evidence in cognitive psychology showing that we are more risk-averse (see the discussion on prospect theory developed by Amos Tversky and Daniel Kahneman).  In other words, we utilize strategies that seek to minimize the risk of loss, rather than ones that try to maximize the chance of reward.  Trust does exactly the opposite.  Fisher writes, "If we offer trust, we are taking a risk that the trust may be betrayed.  If the risk pays off, we may gain a lot, but if it doesn't, we can lose out in a major way."  Trust, then, from a game theoretic perspective, is a payoff-dominant strategy (i.e., one that maximizes the potential payoff), while mistrust is risk dominant (i.e., one that minimizes the potential risk of loss).  As we are seeking to minimize the risk of loss (as opposed to maximizing the chance of reward), it follows that we are more likely to develop mistrust as opposed to trust.  Natural selection, then, favored those with the most highly developed sense of mistrust.    

I will have a lot more to say about trust in future posts.  For now, I encourage you to check out a Medium blog post by Nathan Kinch, entitled "Game theory and the evolution of trust".  Kinch provides a link to an online game by Nicky Case called "The Evolution of Trust".  It's actually a series of games that take about 15-30 minutes (depending on how fast you read) to play, but it will definitely help you to understand why we are evolutionarily programmed to not trust people!  The famous "Tit for Tat" strategy in game theory (see also my posts "Knights, Knaves, and Pawns" and "The Wager" for more), as well as research on the evolution of cooperation also show why we don't trust each other.