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‘Nudges’ Toward Climate Change Action May Discourage More Effective Activism


Whether you’re aware of it or not, you get “nudged” every day. The healthy food that’s been placed at eye level in the store? It’s a nudge to get you to eat better. The 401K savings plan that your company enrolls you in without asking you explicitly to opt in? That’s a nudge to get you to prepare for retirement.

In a new study, Emily H. Ho, a sixth-year doctoral student in Fordham’s Psychometrics and Quantitative Psychology program, has examined the concept of nudging with respect to climate change.

Head shot of Emily Ho

Emily Ho, a sixth-year Ph.D. student in Fordham’s psychology program.

In Nudging Out Support for a Carbon Tax, which was published in the journal Nature Climate Change this June, Ho and her co-authors, David Hagmann at Harvard Kennedy School and George Loewenstein at Carnegie Mellon University, tested a theory that says that if a person is asked to support the idea of a nudge related to combatting climate change—in this case the notion of automatically being enrolled in a program to support renewable energy—they would be less likely to support a carbon tax, which is more painful but also more effective.

After conducting six surveys of more than 4,000 participants, the researchers confirmed that their suspicions were correct. When participants were asked if they’d support the nudge, they said yes. When they were then asked if they’d support a carbon tax, their support went down. But when they were told in advance that the carbon tax was more effective than the nudge, participants supported both initiatives.

Powerful Factors Driving Motivation

Ho said the reticence of the first groups may be explained by a phenomenon known as “single action bias,” which is when you feel that you’ve done enough to address a particular issue, so you decline to do more. She gave the example of a person who recycles and then chooses to take a taxi instead of mass transit.

That’s not to say she wants to put an end to nudging.

“Nudges should actually be used as complements to standard economic policies. It turns out that when we tell people that nudges aren’t that effective [on their own], compared with carbon taxes, and when we tell them carbon taxes can lead to improvements in other areas of their lives, then we find this effect disappears,” she said.

As part of the surveys, some of which were conducted via the crowdsourcing platform Amazon Mechanical Turk, Ho and her colleagues experimented with different ways of asking questions to see if they would get different answers. It made no difference.

“In study two, we told them about the nudge, and then a few moments later, we told them about the tax. Then we asked them, ‘Would you implement a tax, or nothing at all?’ So, they know about the nudge, but we don’t give them the option to implement it. It’s either implement a tax, or implement nothing at all. A lot of people in that case chose nothing at all,” she said.

“If they don’t know about the nudge, they support the tax by 70 percent. The minute people find out about the nudge, their support for the tax drops down 15 percent.”

In order to assess whether education levels and policy-making experience might have an impact on their results, Ho and her colleagues also recruited alumni from the Heinz College of Information Systems and Public Policy at Carnegie Mellon University. The results replicated even in this sample. With each survey, they attempted to craft questions to mitigate or even eliminate the single-action bias, but found that it persisted.

A Time and A Place For Every Nudge

Ho said that despite her research results, nudges can still be a useful tool.

“Nudges are actually quite attractive. They’re typically costless to implement, and they still alter the choice architecture without altering people’s freedom to choose. It’s very flexible as a method for improving behaviors, which is why it’s very popular,” she said. “We’re just identifying that it could hinder the overall goal of getting people to support carbon taxes, which are more effective.”

The idea that people will only support a more difficult solution in addition to an easy one if they’re given enough information makes intuitive sense, of course. What makes this study important, Ho said, is that it provides empirical proof of this in the context of climate change, something that had not existed previously. She also noted that the study’s data, analysis, and results are free and open to the public. In recent years, researchers have had difficulty replicating many studies in the social and life sciences; by making all their data open, as part of the Open Science initiative, Ho and her authors hope others will be able to build off the results of the study, or that it will inspire other researchers to conduct similar experiments.

Ultimately, she said, the study gives policy makers a better understanding of what it may take for them to sell a carbon tax to their constituents.

“I think people have the idea in their mind that a nudge is a magic bullet, because it’s costless and easy to implement. All of those things are true, but our paper is just allowing for the space that that line of thinking can reduce support for more effective actions that should be taken,” she said.


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