February 21, 2025 marked the final session for the Behavioral Science Made Easy Course—and what an insightful five weeks it was! I enjoyed engaging with social and behavior change (SBC) practitioners from South Africa, Ethiopia, Uganda, Nigeria, and Kenya. Their diverse experiences enriched our discussions.
One particularly thought-provoking question stood out: What is the difference between a prompt and a nudge?
I didn’t get a chance to answer this in class, so I’m addressing it here.
The Key Difference: Prompt vs. Nudge
While they both influence behavior, prompts and nudges operate differently.
1. Prompt (Fogg Behavior Model)
A prompt is a reminder at the right moment. It works if the person already has enough motivation and ability to perform the behavior.
Examples of Prompts:
A text message from a clinic reminding you about an upcoming appointment.
A calendar reminder to exercise at a set time.
2. Nudge (Thaler & Sunstein’s Nudge Theory)
A nudge is a subtle change in the choices available that makes a behavior more likely without restricting choices or requiring conscious effort. Unlike prompts, nudges don’t rely on motivation—they shape behavior passively by making the desired choice the easiest one.
Examples of Nudges:
Making flu shots the default during check-ups (unless the patient opts out).
Placing healthy foods at eye level in a cafeteria.
Applying Prompts and Nudges: A Flu Vaccination Example
Let’s say we want to increase flu vaccination rates. Here’s how both approaches could be used:
1. Using a Prompt (FBM)
Text message reminder from a doctor:
“Flu season is here! Walk-in flu shots available at your nearest clinic today. No appointment needed!”
This triggers the behavior at the right moment but still requires motivation and ability (people need to decide to go and make the effort to visit).
2. Using a Nudge (Nudge Theory)
Making flu shots the default option at a check-up:
“Unless you opt out, we’ll include your flu shot in today’s visit.”
Here, no extra effort is needed—patients are automatically guided toward the right choice.
When to Use a Prompt vs. a Nudge
✅ When a Nudge Works Best:
When people are already in the right environment to take action.
Example: A patient already at the clinic is nudged into getting a flu shot by making it the default option.
✅ When a Prompt Works Best:
When people are not yet in the right setting and need a reminder.
Example: A person who hasn’t planned to visit the clinic gets a text message reminding them about the flu shot.
Key Takeaway
In low-resource settings, where accessing healthcare requires effort (travel, cost, time), prompts are probably more effective in encouraging people to go to the clinic, while nudges can optimize their behavior once they arrive.
Is this differentiation helpful for you? This reflection was first posted on my LinkedIn Page on February 22, 2025.