Bad ideas end with a sudden cascade

(written by lawrence krubner, however indented passages are often quotes). You can contact lawrence at:, or follow me on Twitter.


If one person convinces a second, says Blackford, then a third person will be far more likely to agree with the majority view. This effect exponentially increases with each person who agrees with the others. “We soon have a sociological effect whereby everyone knows that, say, a certain movie is very good or very bad, even though everyone might have ‘known’ the exact opposite if only a few early voices had been different,” says Blackford.

The cascade effect can help explain why great movies such as The Wizard of Oz or Heathers can flop at the box office, while terrible movies such as Hangover III rake in millions. It can also steer equally talented people into wildly different levels of success—because one or two influential people vouching for an employee carry a lot of weight.

This means views can be culturally “obvious” even when there’s no objective evidence

“Once a view is popular with the general public, or just within your own ‘tribe,’ it takes a lot of courage even to question it to yourself,” says Blackford. For example, just 50 years ago, homosexuality was banned in many western countries. “It would have been a very brave person to put their hand up and say, ‘There’s nothing wrong with being gay.’”

And so public opinion often stays in place even after private beliefs slowly shift. However, “if there’s a shock to the equilibrium it can collapse suddenly because the appearance of support for it is an illusion,” says Blackford. The fall of the USSR, when fervent belief in communist ideals and leaders faltered in 1989, and the dramatic decline of Christian beliefs in Europe in the 1960s, are two examples of public opinions suddenly shattering.

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