Assessing flexibility in a way that doesn't simply involve asking people if they think they're flexible is difficult. We've been grappling with this problem for a few years and I would love to know a bit more about what you are doing.
of course. We're currently developing an experiment that puts the participants in different moods while they are asked to solve a specific task, hence reach a certain goal (e.g. high performance). The assumption is, that when they are in a mood that helps to reach that goal, they don't have to regulate. However, when the mood constitutes an obstacle for goal attainment, people will have to regulate (up or down). By asking if and how they regulated we will get information on the used strategies, by looking at the performance we'll get information on goal attainment. By doing so, we might have the possibility to evaluate adaptive flexibility (according to Aldao et al. 2015). That's it for the experimental part. The best way to capture the flexibility would be ecological momentary assessment, though. Hopefully, this will be the third step in our project.