12/3/13 Critical thinking web
philosophy.hku.hk/think/fallacy/biases.php 1/2
[TUTORIAL F08] Cognitive biases
Cognitive biases are certain pervasive thinking habits which are
likely to lead to errors inreasoning, but which seem to be a very
common part of human psychology. The study ofcognitive biases is a
very important part of cognitive science and psychology, and
relevantto many other areas, such as economics, management and
education.
F08.1 Some examples of cognitive biases
Confirmation bias: The tendency to look for information that
confirms our existingpreconceptions, making it more likely to
ignore or neglect data that disconfirms ourbeliefs. For example,
when we compare ourselves with others we are more likely toremember
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 isformulated even though it should not affect the
solution. Example: Whether a patientdecides to go ahead with a
surgery can be affected by whether the surgery isdescribed in terms
of success rate or rate of failure, even though both numbersprovide
the same information.
Overconfidence effect (the above-average effect): Many people
tend to over-estimatetheir abilities. Surveys across most areas of
expertise indicate that more than half ofthe 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.
F08.2 Biases relating to probability
Many cognitive biases are related to judgments and reasoning
about probability andstatistics. Here are some examples:
Clustering illusion: The tendency to attribute patterns and
underlying causes torandom events when there are none.
Gambler's fallacy: The error of thinking that a random event can
be influenced by pastrandom events. Example: Thinking that because
a certain number has just come up ina lottery, it is less likely
(or more likely) to come up in the next round.
F08.3 Videos
People often regard things as having higher quality when they
are nicely packaged. Here isa fun video about people's preference
for bottled water:
