This is a longitudinal study that explores how different frequencies of daily consultation on social networks (Facebook, Instagram, etc.) can modify, over time, the social sensitivity of young adolescents to social stimuli of reward and punishment.  

This is a study that uses functional magnetic resonance imaging to analyse the response of different brain regions to situations of reinforcement or punishment that young people face when they consult social networks. 

The results show that, indeed, as seen in the changes in activation of different brain regions, particularly the prefrontal cortex or the amygdala, young people's activity on social networks can change their social sensitivity over time.  

The study is methodologically sound but the sample of experimental subjects, once refined (because it is initially large), falls somewhat short and, in my opinion, is not sufficient for the results to be generalisable to larger populations. That is to say, the conclusions would probably need a larger number of experimental subjects to be generalisable, especially because of the variations observed according to the frequency of consultations that the subjects have on the Internet.