Coincidence judgment in causal reasoning: How coincidental is this?

Area of Science:

• Cognitive Psychology
• Psychology of Causality
• Judgment and Decision Making

Background:

• Extensive research exists on causality, often framed as "how causal is this?"
• Coincidence is conceptually linked to causality, yet lacks a defined psychological construct.
• Prior work defines coincidence as surprising, unlikely-yet-chance-attributed pattern repetitions.

Purpose of the Study:

• To propose and evaluate a psychological construction of "coincidentality".
• To establish coincidentality as the answer to "how coincidental is this?"
• To develop a predictive model for coincidentality judgments.

Main Methods:

• Conducted four experiments using real-life coincidences from an initial diary study.
• Measured judgments of coincidentality, event uncertainty, hypothesis belief, and surprise.
• Evaluated formal models using these judgments as predictors of coincidentality.

Main Results:

• Judgments of uncertainty, belief, and surprise were identified as key predictors of coincidentality.
• A formal model of coincidentality was developed based on these predictive judgments.
• Coincidentality judgments were found to be consistent with the prior definition of coincidence.

Conclusions:

• Coincidentality is a measurable psychological construct.
• It serves as a psychological marker for causal suspicion or discovery.
• High coincidentality may indicate the operation of a new, unidentified causal mechanism.