The Wisdom of Crowds and the Anatomy of a Panic

Major asset markets are generally too large to be overly influenced or pushed around by any one participant, and so are characterized as reflecting the wisdom of the crowd. This is thought of as a positive, as individual participants value different things, have different utility functions and approach and weigh the same incoming information in different ways. The net result, through different individual buys, sells and portfolio shifts gives the ‘best’ value at any one point.

We read an interesting exchange from polymath Sam Harris on the wisdom of crowds the other day that got us thinking about how this works in reality over fairly short, but significant, periods in markets. While the wisdom of crowds notion is true over the medium term, over shorter periods, some participants do cause flows that overwhelm. The events of early 2018 are a good example. The exchange is below; Harris had spoken at an event the previous night in New York with psychologist and economist Daniel Kahneman.

Frank Villavicencio: Sam. I attended & enjoyed it but didn’t get to ask my question: your take on collective decision making. Given the many identified flaws in our individual cognitive abilities, should we consider humans as more optimized for collective, swarm-like decisioning?

Sam Harris: The crowd is only wise when individual errors are uncorrelated. When correlated—as is the case when specific biases are widely shared—there’s no safety in numbers.

Hits the nail on the head. When the errors are correlated, you don’t have a crowd, you have a mob.

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