Cognitive Biases

Read this tutorial, which describes some examples of cognitive biases. These biases are ways of thinking that lead us to make poor inferences. Being able to identify cognitive biases helps us to improve our own reasoning and helps us to assess other people’s reasoning.

Please answer this question first before proceeding:

Namibia is a country in Africa. Do you know how big is Namibia's population? Is it above or below 100 million? Before you continue any further, write down your estimate of the population.

In this tutorial we discuss cognitive biases. These are certain pervasive thinking habits which threaten objectivity and lead to errors in reasoning. Most of us have cognitive biases and it is difficult to get rid of them. Psychologists are interested in cognitive biases because they may tell us about human nature and how our brain is organized. Cognitive biases are relevant to many other areas, such as economics, management, advertising, education, and politics.

Notice that a cognitive bias need not be a fallacy. The anchoring phenomenon just discussed does not seem to be a case where we have made an erroneous deduction. It is just that somehow our attempt to make a guess has been unconsciously influenced.

Cognitive biases are certain pervasive thinking habits which are likely to lead to errors in reasoning, but which seem to be a common part of human psychology. The study of cognitive biases is a important part of cognitive science and psychology, and relevant to economics, management and education.

§1. Some Examples of Cognitive Biases

Confirmation Bias

The tendency to look for information that confirms our existing preconceptions, making it more likely to ignore or neglect data that disconfirms our beliefs. For example, when we compare ourselves with others we are more likely to remember other people's mistakes and less likely to think of our own.

Framing Bias

The tendency to be influenced by the way in which a problem is formulated even though it should not affect the solution. Example: Whether a patient decides to go ahead with a surgery can be affected by whether the surgery is described in terms of success rate or rate of failure, even though both numbers provide the same information.

Overconfidence Effect (the Above Average Effect)

Many people tend to over-estimate their abilities. Surveys across most areas of expertise indicate that more than half of the people think that they are better than the other half with respect to that expertise. For example, more than 50% of the population might think that they have above-average intelligence, but they cannot all be right. So many people tend to over-estimate their abilities and lack insight into their real performance.

§2. Biases Relating to Probability

Many cognitive biases are related to judgments and reasoning about probability and statistics. Here are some examples:

Clustering Illusion

The tendency to attribute patterns and underlying causes to random events when there are none.

Gambler's Fallacy

The error of thinking that a random event can be influenced by past random events. Example: Thinking that because a certain number has just come up in a lottery, it is less likely (or more likely) to come up in the next round.

Source: Joe Lau and Jonathan Chan,
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Last modified: Wednesday, September 11, 2019, 3:08 PM