There are a lot of reasons why it can make sense to go with the majority. Going with the popular view is a shortcut for taking the time and effort to make our own decisions from scratch. We might reason that if others believe it, then it's probably true. But we can also keenly feel the desire to conform to the majority view because it's uncomfortable to hold a different opinion — the easy choice is so often to go with the flow even if, deep down, you disagree. So we get the bandwagon effect.

The bandwagon effect can lead to the Abilene paradox — where a group can make a decision that no one in the group agrees with. On a night out it may lead to just following the crowd, but in a company it could lead to launching a product that no one thinks is good or, more seriously, in safety critical industries like airlines, if people don't feel comfortable speaking up against the group or authority it could lead to accidents.

The bandwagon effect

A deceptively simple, almost too simple to notice, heuristic —  a mental shortcut to solve a common problem — where we consider the likelihood of events by the ease with which relevant instances come to mind. In simple terms, things that we can easily recall or where we can think of examples, we generally consider as more important or more common than other things.

If we were asked to consider the divorce rate in the community, we might evaluate that by considering how many of your acquaintances are divorced. If none of your friends are divorced you’re naturally less likely to think the divorce rate locally will be high.

In many situations it makes good sense to give some credence to what you remember easily. However, in situations involving probabilities in particular the heuristic will lead us predictably astray such that more often I think of it as an availability bias — a predictable pattern of thought and behaviour leading to incorrect conclusions. 

So, the vividness of shark attacks causes us to overrate how likely they are to actually occur. Or we’re more likely to worry about lions than hippos, even though hippos kill more people each year than lions. Or the risk of being struck by lightning vs stuck by a car crossing a road. Or, the prevalence of violent crime on the news compared to the likelihood of you being a victim. Or the fact that it’s cold outside and yet the planet is gradually warming.

Here’s a 1973 Kahneman and Tversky paper: Availability: A Heuristic for Judging Frequency and Probability

The availability heuristic (and bias)

These terms come around a bit, and I wanted to get them clear in my head so I understood the difference.

Cognitive bias: predictable patterns of thought and behaviour leading to incorrect conclusions. Things like anchoring, where we are predictably led astray by the presence of a previous number we have seen.

Heuristic: mental short-cut to solve common problems. Things like social proof, how if others seem to like something that’s a short-cut for we’ll probably like it.

Logical fallacy: a flaw in our reasoning leading to a faulty argument. Things like the sunk cost fallacy, where we will sometimes make ourselves unhappy in the future because of something we’ve already done that we can’t change. The logical step would be to choose the path that would make you happiest in the future regardless of any sunk costs up to now. Turns out that’s hard.

Cognitive bias, heuristic, logical fallacy: hidden features of the mind

Not the standard physics laws of expansion.

Work expands to fill the available time — also known as Parkinson's Law

Stuff expands to fill the available space — also known as Jono's Law

Cost expands to fill the available budget — also known as life

After grandiosely naming "Stuff expands to fill the available space" as Jono's Law, I came across "Ryan's Application of Parkinson's Law: Possessions increase to fill the space available for their storage," in Arthur Bloch's Murphy's Law Book Two, p 84, which, at least, is perhaps not as pithy.

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Category: heuristic