Why the Conjunction Effect Is Rarely a Fallacy: How Learning Influences Uncertainty and the Conjunction Rule.
Phil Maguire1, Philippe Moser1, Rebecca Maguire2
1Department of Computer Science, Maynooth University, Maynooth, Ireland.
Frontiers in Psychology
|July 20, 2018
Summary
The conjunction fallacy may not be a fallacy when people can learn from new information. This study shows that reducing uncertainty and allowing learning mitigates the conjunction effect in decision-making.
Area of Science:
- Cognitive Psychology
- Decision Making
- Behavioral Economics
Background:
- The conjunction fallacy, where people judge a conjunction of events as more probable than one of its constituents, is often considered a cognitive error.
- This interpretation assumes shared knowledge and no privileged information, which is rare in real-world scenarios.
Purpose of the Study:
- To formally prove that the conjunction rule does not apply in scenarios where learning from outcomes is possible.
- To investigate the role of subjective uncertainty and learning in mitigating the conjunction effect.
Main Methods:
- Formal proof based on an existing model of surprise.
- Experiment 1: Rephrasing scenarios to eliminate subjective uncertainty.
- Experiment 2: Reducing subjective uncertainty by allowing participants to learn about scenario mechanisms.
Main Results:
- The conjunction rule is shown to be inapplicable in typical scenarios with potential for learning.
- Experiment 1 demonstrated a mitigation of the conjunction effect when subjective uncertainty was removed.
- Experiment 2 showed a diminished conjunction effect when participants learned about the scenario's underlying mechanism.
Conclusions:
- The conjunction effect arises from the unnatural assumption of shared knowledge in verbal descriptions.
- In real-world situations, people naturally assume learning is possible and subjective uncertainty applies, thus questioning the universality of the conjunction fallacy.
Related Concept Videos
04:08The Uncertainty Principle
32.6K
Werner Heisenberg considered the limits of how accurately one can measure properties of an electron or other microscopic particles. He determined that there is a fundamental limit to how accurately one can measure both a particle’s position and its momentum simultaneously. The more accurate the measurement of the momentum of a particle is known, the less accurate the position at that time is known and vice versa. This is what is now called the Heisenberg uncertainty principle. He...
32.6K
02:46Uncertainty in Measurement: Reading Instruments
53.2K
Counting is the type of measurement that is free from uncertainty, provided the number of objects being counted does not change during the process. Such measurements result in exact numbers. By counting the eggs in a carton, for instance, one can determine exactly how many eggs are there in the carton. Similarly, the numbers of defined quantities are also exact. For example, 1 foot is exactly 12 inches, 1 inch is exactly 2.54 centimeters, and 1 gram is exactly 0.001 kilograms. Quantities...
53.2K
03:34Uncertainty in Measurement: Significant Figures
83.3K
All the digits in a measurement, including the uncertain last digit, are called significant figures or significant digits. Note that zero may be a measured value; for example, if a scale that shows weight to the nearest pound reads “140,” then the 1 (hundreds), 4 (tens), and 0 (ones) are all significant (measured) values.
83.3K
02:55Exceptions to the Octet Rule
37.8K
Many covalent molecules have central atoms that do not have eight electrons in their Lewis structures. These molecules fall into three categories:
37.8K
00:59Uncertainty: Overview
1.7K
In analytical chemistry, we often perform repetitive measurements to detect and minimize inaccuracies caused by both determinate and indeterminate errors. Despite the cares we take, the presence of random errors means that repeated measurements almost never have exactly the same magnitude. The collective difference between these measurements - observed values - and the estimated or expected value is called uncertainty. Uncertainty is conventionally written after the estimated or expected value.
1.7K
02:36Lewis Symbols and the Octet Rule
81.2K
Chemical bonds are complex interactions between two or more atoms or ions, which reduce the potential energy of the molecule. Gilbert N. Lewis developed a model called the Lewis model that simplified the depiction of chemical bond formation and provided straightforward explanations for the chemical bonds seen in most common compounds.
81.2K