So far, research suggests that transparency has minimal influence on the effectiveness of the nudge.^{1, 2} Still, it’s hard to believe everyone reacts the same way. For one, some people may experience psychological reactance which theoretically could diminish the nudge but evidence found only weak links.³

One possible reason? Previous research didn’t consider how long participants took to respond. In psychology, response time is often a clue to decision difficulty: tougher choices usually take longer.⁴ Since reactance is believed to draw from the same cognitive resources as difficult decisions, the impact of nudge transparency is inherently intertwined with response time and reactance.⁵ This is where Schütze and colleagues come in to fill in the gap in the transparency discourse. 

To better understand the consequences of nudge transparency, the researchers recruited 623 participants to complete an online experiment. Each participant was asked to decide how much of a €10 endowment they wanted to donate to a charity foundation. Participants were randomly assigned to one of five different nudging conditions: no default donation, a €10 default donation amount, €0 default donation amount, and two transparent versions of the €10 default amount (one in regular plain text and one highlighted in bold). 

In both transparent nudge conditions, the choice was accompanied by the following statement: “Based on scientific findings, the donated amount is pre-selected so as to achieve maximum donations.” To incentivize participants to decide as realistically as possible, they were informed of a 1 in 10 chance of receiving the stated amount for themselves. Creating situations where choice leads to real outcomes helps raise the stakes in participants’ decisions which should in turn encourage fuller engagement in the study.

After participants were shown the nudge, a survey was administered to collect insights on donation amount, psychological reactance, and adherence to the default. The researchers also tracked response time to analyze decision-making difficulty. 

Like past studies, the experiment revealed that transparency doesn't weaken the nudge for the average participant. But only looking at psychological reactance didn’t tell the full story. Transparency was also found to have varying effects on people with different reaction times. For individuals who took longer to decide, transparency increased the likelihood they’d adhere to the default donation amount, while no influence was observed among fast decision-makers. Psychological reactance also appears to interact with response time. Highly reactant individuals with longer response times were more likely to reject the default and donate nothing, especially when the transparency was emphasized in bold. Overall, the average donation was €4-5 across all treatments. Transparency boosted donations in participants with longer response times (€5.73 vs. €4.20). 

This study challenges the fear that making nudges visible to the people being influenced makes them weaker. Instead, the results suggest that transparency can reinforce nudges for many individuals, particularly those who take time to reflect before acting. For those who are quicker on their feet, transparency didn’t hurt donations either, showing that there is no need for nudges to operate behind curtains.

Transparent nudges can build trust and legitimacy—two ingredients behavioral science critics are looking for when it comes to the ethics around behavioral interventions. By explaining the intent behind a nudge, designers may increase acceptance without sacrificing impact.

That said, reactance isn’t irrelevant. Highly reactant individuals may push back when they sense influence. This points to the value of flexible, adaptable, and context-sensitive nudges that account for different psychological traits.

However, as this experiment was conducted online and only on one nudge type, future research should explore whether these patterns hold in real-world scenarios with higher stakes and different choice architectures. The key insight is that nudge transparency's impact isn't uniform; it crucially depends on decision difficulty and individual psychological traits.

In an era where carefully tailored nudges shape everything from what we buy to how we vote, trust in choice architecture is crucial. A nudge that works only in the shadows risks backlash when exposed. But a transparent nudge can align behavior change with democratic values and informed consent.

Transparency also helps bridge a gap in public discourse. Rather than debating whether nudges are ethical, this research suggests a middle ground: nudges that are both effective and honest. When people know what’s happening and why, they’re often more willing to participate.

This study brings a different angle to the ethical nudging debate: transparency and influence are not necessarily at odds. They can be allies when accounting for how people make decisions. The findings suggest that being transparent about nudges might not only be ethical but effective too, especially for those facing difficult decisions. For designers of behavioral interventions, whether in policy or products, the research demonstrates that transparency could be a powerful tool, not a weakness. When you next encounter a nudge that discloses itself, recognize that transparency might be the very factor that enhances its influence, particularly if you're one to carefully consider your choices.

1. Bang, H., Shu, S., & Weber, E. (2020). The role of perceived effectiveness on the acceptability of choice architecture. Behavioural Public Policy, 4(1), 50–70.
2. Loewenstein, G., Bryce, C., Hagmann, D., & Rajpal, S. (2015). Warning: You are about to be nudged. Behavioral Science & Policy, 1(1), 35–42.
3. Bruns, H., Kantorowicz-Reznichenko, E., Klement, K., Jonsson, M. L., & Rahali, B. (2018). Can nudges be transparent and yet effective? Journal of Economic Psychology, 65, 41–59.
4. Alós-Ferrer, C., & Garagnani, M. (2022a). Strength of preference and decisions under risk. Journal of Risk and Uncertainty, 64(3), 309–329.
5. Laurin, K., Kay, A. C., Proudfoot, D., & Fitzsimons, G. J. (2013). Response to restrictive policies: Reconciling system justification and psychological reactance. Organizational Behavior and Human Decision Processes, 122(2), 152–162.