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## What is a conjunction fallacy?

Conjunction fallacy refers to a cognitive bias caused by incorrectly calculating probabilities. It is a judgment based on subjective probability rather than objective probability. Conjunction fallacies are also called federation fallacy, connection fallacy.

## Characteristics of conjunction fallacy

Intuitive judgment is possible due to conjunction fallacy. (However, it is most likely not accurate.)

Conjunction fallacies lead to errors in probability calculations because intuitive thinking instead of rational thinking.

Because of the conjunction fallacy, we mistakenly think that (probability of event) x (probability of event) is greater than (probability of event).

## Examples of conjunction fallacies

Due to the conjunction fallacy, you
can make irrational judgments in real life as shown below.

While
waiting for the roller-coasters, the person next to you is playing a mobile game happily.

Which
of the following is that person is most likely to be?

1. A person who likes
roller-coasters and mobile games.

2. Someone who hates roller-coasters and mobile games.

3.
Someone who likes to play mobile games.

In most conjunction
fallacy, you can choose 1. You can guess that someone who likes roller-coasters must have come to the amusement park and played the mobile game. However, the most probable one with probability is 3.

Because if we analyze the
probability of each (arbitrarily, let's assume that likes to amusement parks is
0.7[70%], dislikes is 0.3[30%], and likes mobile games is 0.9[90%]. You can change the
probability of each as you like. .)

1 is 0.7 * 0.9 = 0.63 [63%]

2 is
0.3 * 0.9 = 0.27 [27%]

3 times 0.9 = 0.9 [90%]

will become
In other words, the product of (probability 1) and (probability 2) cannot exceed
(probability 2). (However, probability 1 and probability 2 cannot exceed 1.0
[100%].)

So, in the example above, the highest probability is number
3.

## Conjunction fallacy three line summary

-Conjunction
fallacy lead to incorrect calculation of probabilities.

-Conjunction
fallacies lead to an erroneous judgment that a sequence of events is more likely
than a single event.

-Conjunction fallacies are also called connection fallacy, federation fallacy.