"Violent behaviour is strongly influenced by cultural and social norms; so efforts to prevent violence must consider how social pressures and expectations influence individual behaviour. Interventions that attempt to alter cultural and social norms to prevent violence are among the most widespread and prominent.
Rarely, however, are they thoroughly evaluated, making it currently difficult to assess their effectiveness. Rigorous scientific evaluations of interventions that address norms supportive of violence present particular, but surmountable,
challenges, which partly explain their scarcity. Nevertheless, a number of positive results have been reported.
Although the effect of mass media interventions, aimed at whole societies, on levels of violent behaviour have seldom been evaluated, their success in addressing other public health issues (smoking and drink-driving, for instance) suggests they have a critical role to play in the prevention of violence.
Furthermore, edutainment initiatives, such as Soul City in South Africa, have shown promise in changing cultural and social norms and attitudes associated with violent behaviour. While it is difficult to ascertain the effectiveness of laws and policies in changing social attitudes, legislation that is enforced can send clear messages to society that violent behaviour is not acceptable."
Taken from: WHO, Summary, Violence Prevention The Evidence, WHO https://www.who.int/violence_injury_prevention/violence/norms.pdf