Psychology

The Conjunction Fallacy is a commonly observed phenomenon people regularly judge a compound event to have a greater amount of probability than a component event of the compound event.
Many different theories exist to explain why this fallacy occurs. It was first posited that the fallacy occurred due to the way the question was framed, however better and clearer ways of framing the question do not usually result in better results (Tversky  Kahneman, 1983).

Finding out why the conjunction fallacy occurs is extremely important in understanding human cognition. Humans commonly consider themselves to be the only rational creatures in existence, the widespread observation of the conjunction fallacy shows that this may be a distorted self-view.
The existence of the conjunction fallacy has widespread implications for human cognition. It implies that people regularly misestimate probabilities of events in their daily lives.

The judicial system often requires juries composed of members of the general public to hear two competing stories, the jurors are then required to decide which story they consider more plausible, the existence of the conjunction fallacy shows that people may regularly regard the more improbable narrative as the more plausible one (Tversky  Kahneman, 1983).

The economic system of modern societies is built upon the estimation of probabilities the existence of the conjunction fallacy implies that the markets may not be trusted to undertake the most rational course.

Since this error is so widespread it is possible that many actions undertaken by governments that have great implications for nations and humanity at large may be based on threats which have very low probabilities while ignoring much greater threats.

Thus we can say that the existence of this fallacy has widespread implications for humanity, human societies and human individuals and it is most important to study this fallacy further, explore why it occurs, and make people aware of its existence and to teach them to avoid falling into this fallacy when making any decisions.

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Conjunction Error Rate across my subjects
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Conjunction Error Rate across the groups subjects
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Average Error Rate of each subject across all scenarios
The results to the experiment show that the majority of people are commonly affected by the conjunction fallacy and certain people are more prone to the fallacy than others.

The results of this experiment, suggest strongly that the general public is getting more and more informed about the conjunction fallacy. However although such people are not naive anymore when replying to certain questions this has probably occurred due to the recognition of certain types of questions containing conjunctive sentences as trick questions where in the correct answer the conjunction always has a lower probability than each disjunction. It is possible that these people are relying on this learned trick when giving their answers and the correct answers may not reflect a greater general understanding of the logic or the mathematics of probability. As such people are just as likely to fall prey to the conjunction fallacy when taking decisions in their real lives even though they answer correctly questions put to them in certain ways.

The results also suggest that people are more likely to fall prey to the conjunction fallacy when faced with questions containing certain scenarios more than others. It shows that the framing of the question andor prior knowledge, biases or stereotypes have a definite effect on whether or not the conjunction fallacy occurs. Scenario 3, particularly elicit a high rate of erroneous responses. As such the conjunction fallacy cannot be deemed to be completely the result of a cognitive deficiency in the subject, but possibly may be partially attributed to a lack of precision in framing the question.
Some suggest that this fallacy occurs because people rely on certain rules of thumb for judging the probability of an event rather than rational thinking. People judge the independent possibilities of each event separately and then use an incorrect rule of thumb to combine the two probabilities.

By the use of introspection, in the original Linda Problem, the obvious reason behind peoples preference of the second statement seems to me to be that in the in the second statement people immediately recognize feminism as being the sort of liberal movement that an outspoken female philosophy major interested in social justice etc. would be involved in, whereas a bank tellers job seems to be something expect to have no relation to, or possibly even have a negative correlation to an education in philosophy.

It seems that peoples thinking is geared toward getting a fast solution to any problem faced by them rather than the best or the most optimum solution. After reading or hearing the premises, people get the picture of a certain type of individual in their minds, when they hear or read the two statements they move immediately to select the one that contains some information that conforms to the picture they have in their mind (Hertwig  Herzog, 2009).

In the variant of the Linda problem where in the first statement, where the experimenter attempts to make clear that Linda the bank teller, may or may not be a feminist in the first statement, people still prefer the second statement due to the fact that it explicitly confirms their earlier suspicions about Linda while the first statement does not confirm at all the internal stereotype of a liberal female being a feminist while the possibly negative correlation between an education in philosophy and a job as a bank teller is not a very strong negative correlation people are often forced by circumstances to take up jobs in fields that are not related to their education.

This experiment shows that most peoples manner of thinking and cognition depends more upon their biases and preconceived notions about a scenario rather than clear logical thinking. Biases and stereotypes allow people to conduct quick judgements. Human life often requires us to make quick decisions and fast and instant reactions to events. These fast reactions are probably necessary for human survival. Sometimes the ability to make fast judgements and reactions results in less than optimal solution, however in many situations, any solution is better than having no solution at all (Hertwig  Herzog, 2009).

The effect of biases and preconceived notions is overwhelms rational thinking especially when an individual is required to pass judgements upon other people or groups of other people, people are less likely to fall prey to the conjunction fallacy when the question posed to them involves not people but inanimate objects. Hence when people are posed a question about an urn filled equally with poker chips and marbles and they are asked that if one item is extracted from the urn is it more likely that the object is a marble or that it is a blue marble, they usually correctly select the likelihood of the object being a marble as being greater than the likelihood of it being a blue marble (Schwartz  Goldman, 1996). This shows how people have different modes of thinking for different circumstances and may unknowingly fall into irrationality when thinking of other people.