It is not easy to apply quantitative methods of measurement for issues that are multifactorial and a significant part of the composition factors is qualitative.
The best instrument, in my opinion, is in-depth interviews, with the informed consent of the participant, once the confidence has been obtained to respond with freedom.
Though I agree with the ideas proposed by researchers in this discussion, Prof. Dragoljub's views on the unquantifiable nature of the human brain's ideas/approaches is spot on.