During the COVID-19 pandemic, ensuring widespread compliance with preventive measures like social distancing was critical to mitigating the spread of the virus. However, despite extensive public health campaigns, many individuals struggled to consistently adhere to these guidelines. This highlighted the need for innovative strategies to enhance public health communication and encourage lasting behavioral changes, particularly as societies transitioned into post-quarantine phases.

To address these challenges, our team at Heurística Lab conducted a research initiative grounded in behavioral science principles. The primary objective was to evaluate the effectiveness of specific communication strategies in promoting compliance with preventive behaviors in a hypothetical post-quarantine scenario.

Understanding the barriers

Through a literature review, we identified two critical areas for exploration:

• Messenger credibility: The identity of the messenger often determines the reception and influence of a message. Leveraging the "messenger effect," we investigated whether public health authorities, such as the Ministry of Health, or familiar social figures, like a best friend, would be more effective in persuading individuals to avoid social gatherings post-quarantine.

• Clarity in communication: Clear communication is essential in guiding behavior. We explored whether presenting contrasting visual stimuli—showing both appropriate and inappropriate behaviors—would enhance understanding and adherence to key measures, such as maintaining a minimum social distance of one meter.

The experiments

To investigate these issues, we conducted two experiments with 586 participants from 27 countries, primarily in Latin America. The experiments explored the following:

1. The Messenger Effect

Objective: To test whether the person delivering a message (a public health authority versus a best friend) affects how people respond to it.

Design: Participants read a scenario where they considered attending a social gathering two weeks after quarantine ended. They were randomly shown one of two messages, both encouraging them to stay home:

• Message 1: From the Ministry of Health.

• Message 2: From their best friend.

Participants were asked:

• How likely they were to attend the gathering.

• How likely they were to share the message.

Results:

• Attendance: Messages from the Ministry of Health reduced the likelihood of attending the gathering by 19% compared to the same message from a best friend.

• Sharing: Participants were 22% more likely to share the Ministry’s message.

2. Joint vs. Separate Stimuli Evaluation

Objective: To explore whether showing people both good and bad examples of behavior (together or separately) improves understanding of social distancing rules.

Design: Participants were shown images related to social distancing:

• Image A: Undesirable behavior (people not keeping distance).

• Image B: Desirable behavior (people keeping distance).

• Images A + B: Both behaviors shown side by side.

Participants rated:

• How well the images showed the rules.

• How effective the images were at teaching the correct behavior.

Results:

• Showing both images together (A + B) helped participants better understand what to do and what to avoid.

• Joint images were rated as the most effective way to teach social distancing.

Reflections

This research highlights the critical role of behavioral insights in designing effective public health campaigns. By addressing psychological and perceptual barriers, the study demonstrated how small adjustments to messaging—such as choosing the right messenger or using comparative visuals—can lead to significant improvements in adherence to preventive measures. These strategies have implications beyond COVID-19, offering valuable lessons for any initiative requiring widespread behavioral change.

Key takeaways

• Credibility and authority significantly enhance message effectiveness.

• Visuals showing both correct and incorrect behaviors are more impactful than isolated examples

• Small, evidence-based changes can transform communication strategies.