Exploring the relationship between psychological flexibility and self-report and task-based measures of cognitive flexibility

Acceptance and Commitment Therapy (ACT) interventions aim to increase psychological flexibility (PF) leading to positive treatment outcomes. It has been suggested that successful development of PF may depend on cognitive flexibility (CF). There is however a lack of clear empirical evidence accounting for the relationship between the two constructs. The current study investigated the relationship between PF and CF in a large nonclinical sample of younger adults ( N = 246). Participants completed self-report measures of PF, and both self-report and task-based measures of CF. Results indicated that self-report, but not task-based, CF correlated with and predicted PF ( r = −0.49, 95% BCa CI [−0.58, −0.38], R 2 = 0.236). The results are discussed with reference to rule-governed behaviour, approaches to measurement, and ACT, with suggestions for future research. • Increased self-report cognitive flexibility is associated with psychological flexibility. • Task-based cognitive flexibility is not associated with psychological flexibility. • Self-report and task-based measures capture different aspects of cognitive flexibility. • Cognitive flexibility may help augment Acceptance and Commitment Therapy effectiveness. • Considering impairments in self-report cognitive flexibility may be valuable for ACT treatment interventions.