Encouragement of learning is considered central to resilience of complex systems such as social-ecological systems (SESs). However, despite the consensus on the centrality of learning, our understanding of the details of how learning should be encouraged remains far from settled. This study investigates that puzzle by examining existing data of a behavioral experiment of a SES that involves endogenous group learning. We generate new hypotheses regarding how learning should be encouraged by comparing the learning process undergone by 21 groups of human-subjects. Our findings suggest that under environmental stability, groups may be able to perform well without frequent outer-loop (or double-loop) learning. As long as they tightly coordinate for shared strategies with active monitoring and reflection and user participation, they can still succeed. However, such groups may be fragile under environmental variability. Only groups that experienced active outer-loop learning and monitoring and re ection may remain resilient under environmental variability.