The claim that cognitive psychology and behavioral economics study the framing effect is common knowledge, as the framing effect is a foundational concept extensively documented and investigated across both fields.
The claim states that cognitive psychology and behavioral economics study the framing effect. This is a matter of established academic categorization and common knowledge in the behavioral sciences, so no citation is strictly needed, although multiple retrieved papers confirm that cognitive psychology and behavioral economics (as well as related fields like behavioral finance) actively study cognitive biases such as framing. Therefore, the balance verdict is COMMON_KNOWLEDGE.