Notes
[1] Disclosure There was no funding involved in the study.
The parents received a letter informing them about the study and if they did not consent that their child should participate, they were asked to return a slip with their signature to the teacher.
The study followed the Nordic ethical guidelines for psychologists, and according to Danish law for this type of study, no other approval is needed.
[2] Conflicts of interest Conflicts of interest The author declares no conflict of interest.