Psychologically speaking, we could say that in our life we do not have events happen to us, but we interpret events that happen to us. The psychological impact is determined by perception and interpretation. For example, when faced with a highly demanding task that we do not know if we will be able to perform satisfactorily the first time, when our hands start sweating and our heart starts racing, we may consider that stress is manageable and potentially beneficial, as it prepares us for action; or that stress is inherently negative and reduces our performance, health and well-being. One may understand that our ability to perform certain tasks can be developed with practice and effort, or that it is fixed and cannot be improved - so if we fail, there is little point in trying any further. In psychology, for some years now, the term "growth mindset" has been used to mean the interpretation that stress can offer us something positive and that our abilities can increase, as opposed to seeing stress as inherently limiting and abilities as immutable or beyond our control.

Across six studies, with US samples of more than 4,000 adolescents and young people from different social classes, the researchers show how a small, simple, online, half-hour intervention programme focused on conveying this growth mindset has beneficial effects on several levels. When participants have to go through stressful situations typical of their tasks and obligations at their age, these (small) effects show up in cognitive measures (how they interpret what happens to them), improvements in psychological well-being, healthier physiological levels or better academic performance. These effects are clearest among those adolescents and young people who, at the start of the study, have a low growth mindset. It is important to emphasise that the intervention, because of its simplicity, can be easily extended.

The study is comprehensive in tasks and samples. The analyses are adequate, although it is surprising that some common cut-off points are changed as to whether an intervention is effective. This potential problem, in my view, is diluted by the convergence of results across studies.

Unnecessarily, the authors attempt to give a social reading to these results. In an environment where the mental health of adolescents and young people seems to be declining, the authors understand that it is necessary to prepare them for a competitive and highly demanding world and that such a growth mindset can be helpful. They attempt to counter this with an alleged societal narrative that adolescents and young people are encouraged to be fragile and to avoid what may be upsetting. They offer no evidence for this narrative, nor do they indicate that, in the face of a competitive world, one can prepare for battle, but also try to build a society in which pressure is reduced (this second option is not even discussed). The social narrative they are trying to build with their study is gratuitous, although this does not detract from an intervention that, if confirmed, would be effective and easily generalisable to many people, due to its low cost and ease of access.