If you are faced with a question and you don’t know the answer, using the representativeness heuristic is a way of coming up with a plausible solution.
The representative heuristic is when our brains quickly assess the probability of several possible options and plump for the most probable.
For example, if you get stuck in traffic near a sports stadium on a Saturday, your guess that there is a match on and you should have checked before you set off is likely to be right.
The representativeness heuristic
The snappily named representativeness heuristic is one of a group of heuristics – mental shortcuts – put forward by the psychologists Amos Tversky and Daniel Kahneman in the 1970s.
Not having all the information to conclusively answer a question, the brain searches for reference points to come up with an answer.
Sometimes intuitive judgment, or relying on stereotypes, is likely to be right. The person just caught speeding in the souped-up sports car with the big exhausts is more likely to be a young male driver than an old woman.
This conclusion can reasonably be drawn from the fact that there are many more young male drivers of modified sports cars than elderly female ones. But context can easily be forgotten.
Kahneman gives an example of a woman reading the New York Times on the New York subway and asks whether it is more likely that she has a PhD or does not have a college degree.
“Representativeness would tell you to bet on the PhD but this is not necessarily wise,” he says. “You should seriously consider the second alternative, because many more non-graduates than PhDs ride in New York subways.”
He warns of excessive willingness to predict the outcome of events. “To be useful, your beliefs should be constrained by the logic of probability.”
Not remembering to put your assumptions into context can lead people to draw conclusions that are not backed up by statistics and are about as reliable as visiting the woman with the crystal ball on the pier.
There are many recognised examples of where your intuition or the representativeness heuristic can seriously let you down and sometimes cost you money.
The gambler’s fallacy is the idea that past events will influence future ones even though the results are independent of each other.