More on heuristics

The cognitive psychology Thinker has a few great minitutorials that give examples illustrating some of the most common heuristics.

From the site overview:

A number of factors can affect how we go about making decisions, but it is unusual for us to make a decision completely objectively and rationally; rather we usually bring biases from our prior beliefs or experiences into the situation. As a result, we often use "rules of thumb," or heuristics, to help us. These heuristics allow us to have an idea about how to weigh our options, even though they might sometimes lead us astray. Likewise, sometimes the way our options are worded, or "framed," may lead us to think differently than we might otherwise. Finally, we often allow prior experience or outcomes to guide our approach to a decision, even though, again, that approach may not be the best way to go.

Representativeness bias

This week's AMNews, the newsletter of the American Medical Association, includes an excerpt from Dr. Jerome Groopman's book How Doctors Think (amazon.com book info). The excerpt discusses a case of missed diagnosis of cardiac disease in a healthy man and gives a great example of the representativeness heuristic in clinical decision-making.

Groopman notes of the case and how it illustrates this kind of bias:

The mistake Croskerry made is called a representativeness error: your
thinking is guided by a prototype, so you fail to consider possibilities that
contradict the prototype and thus attribute the symptoms to the wrong
cause.