"Representativeness Heuristic
May 28, 2010
by davidmcraney

The Misconception: Knowing a person’s history makes it easier to determine what sort of person they are.

The Truth: You jump to conclusions based on how representative a person seems to be of a preconceived character type.

Without filters, the world around you is chaos.

Reducing chaos into a manageable mental state is a constant battle, and over time you develop shortcuts to cognition.

Categories are a great way to make sense of things. When it comes to strangers, your first instinct is to fit them into archetypes to quickly determine their value or threat.

These constructs are called representativeness heuristics.

A study conducted by Mellers in 2001 is often referenced to demonstrate this.

It goes like this:

Linda is a 31-year-old woman who is single. She is considered outspoken and very bright. She majored in philosophy on college. As a student, she was deeply concerned with discrimination and social issues. She participated in several demonstrations. (From “Social Psychology” by David C. Meyers)

Which is more likely?

* Linda is a bank teller
* Linda is a bank teller and active in the feminist movement.

Most people who read the above description pick the second answer, although it is statistically more likely she is a bank teller. There are more bank tellers in the world than bank tellers who are feminists, no matter what sort of background they may have.

Here is another one, from an experiment by Fischhoff an Bar-Hillel in 1984:

Seventy engineers and 30 lawyers were interviewed, and here is a random sample from their interviews:

He is a twice divorced man who spends most of his free time at a country club. He regrets following in his father’s footsteps. He wishes he hadn’t spent so much time in college on academics and instead spent more time socializing so he wouldn’t be so quick to argue with people. (also from “Social Psychology”)

So, which is more likely?

* This guy is a lawyer
* This guy is an engineer

Well, statistically, the chances are far greater this guy is an engineer since 70 of the 100 people interviewed were engineers, but 80 percent of people pick lawyer.

This is one of hundreds of studies which shows you don’t naturally think in statistical, logical, rational terms. You first go to your emotional core and think of people in terms of narratives and characters which match your preconceived notions of the sort of people you have been exposed to in the past.

Writers of fiction know this and use it to make characters who are compelling whether by fitting into an archetype or by breaking from expectations.

Representativeness heuristics are useful, but also dangerous. They can help you avoid danger and seek help, but they can also lead to generalizations and prejudices.

When you expect people to be a certain way because they seem to represent your notions of the sort of people in that category, you are not so smart."