Abstract
The Complex Card Matching Task (CCMT) is a computerized assessment designed to measure the balance between exploration and exploitation in decision-making. Similar to the Wisconsin Card Sorting Test (WCST), participants must infer the current matching rule through trial and error and adjust their behavior when the rule changes. However, unlike the WCST, which emphasizes set-shifting after rule discovery, the CCMT is specifically designed to capture the dynamic interplay between exploratory sampling and exploitative responding on a trial-by-trial basis. In the CCMT, participants engage in a card-matching game where they explore to identify the active rule and exploit their knowledge until the rule unexpectedly shifts, prompting renewed exploration. The CCMT can be implemented as a behavioral or pupillometry experiment. It is programmed in PsychoPy Coder and offers flexibility in both structure and duration, with customizable blocks and trials. Key data metrics are easily extracted and preprocessed using Jupyter/Python notebooks. All files are available to download on GitHub.