What does the conjunction fallacy relate to in decision-making?

The conjunction fallacy refers to the tendency for people to assume that specific conditions are more probable than a single general one. This is closely associated with the representativeness heuristic, which is a mental shortcut that relies on immediate examples that come to mind when evaluating a specific situation.

When individuals use the representativeness heuristic, they often ignore the actual probabilities of events and instead focus on how much a scenario resembles their stereotypes or expectations. In the context of the conjunction fallacy, this means that people might incorrectly judge the probability of a conjunction of two events to be greater than the probability of one of the events occurring alone. For example, if someone is given descriptions that match a stereotype, they may believe that a more detailed, specific scenario (like a person being both a bank teller and a feminist) is more likely than a broader scenario (the person being just a bank teller), even though the latter must account for more possibilities.

This fallacy highlights important insights into how decision-making can be distorted by cognitive biases, illustrating the impact of representativeness in our reasoning processes. Understanding this concept can help individuals recognize their own decision-making patterns and the potential for error stemming from reliance on heuristics.