Improving preventive health behaviors in the COVID-19 crisis: a messaging intervention in a large nationally representative sample

Public health communication play an important role in the fight against COVID-19. We used five well-established psychological levers to improve on the efficacy of two posters used by the French authorities (one on protective behaviors and one on proper handwashing). The five levers were: simplification (streamlining the posters), sunk costs (emphasizing the costs already paid to fight the pandemic), morality (emphasizing the duty to help others), self-protection (emphasizing the personal risks), and disgust (pointing out and illustrating that not following the protective behaviors or proper handwashing had consequences that should trigger disgust). We tested on a large (N = 3000) nationally representative French sample whether versions of the posters using these levers, compared to a control condition, were clearer, better recalled, and increased people’s intention to follow the posters’ recommendations. On the whole, there were no effects of the manipulations on any of the measures. The only consistent pattern was that the control protective behavior poster was better recalled than the alternatives (except for the simplified version), possibly because it contained one fewer message. The lack of effect on behavioral intentions might be attributed to the potential saturation in terms of health communication at the time of the experiment. Our results--mostly null and potentially negative--confirm the importance of testing interventions before using them in a public health campaign, even if they are grounded in successful past interventions.