If change is hard, lasting change is even harder. Researchers and policymakers are investing heavily in interventions to help people live healthier and more successful lives, but long-term results are far from guaranteed, even for interventions that work in the short run. Yet it is that long-term impact that investors desire and participants need, whether interventions aim to increase voting rates, encourage physical fitness, or incentivize retirement savings.
Harvard researchers Erin Frey and Todd Rogers have identified four pathways through which behavior change interventions can achieve long-term impact. Although the specific strategies vary according to the type of intervention, the same principles apply across fields, the researchers write in an article for Policy Insights from the Behavioral and Brain Sciences. That means that how interventions are designed matter as much as what they do.In their article “Persistence: How Treatment Effects Persist After Interventions Stop,” Frey and Rogers illustrate the four pathways using an example of a successful program to reduce homeowners’ energy consumption. In a study of over 200,000 households, the energy efficiency firm OPOWER sent out home energy reports (HERs) that showed consumers how much energy they used relative to their neighbors. The goal was to apply a kind of positive peer pressure to encourage people to use the same amount or less energy than their neighbors. The strategy, based on research from social psychology, worked. People who received HERs several times a year reduced their energy consumption relative to a control group who did not receive the reports, and at a rate similar to increasing energy costs from 19% to 31%. Most impressively, those who received the reports for two years continued to show lower consumption over the subsequent two years than those in the control group.
Frey and Rogers’ review of research suggests that the following principles may have helped account for the program’s long-term success and point to promising strategies for other interventions:
- Building psychological habits. Habits develop when people come to associate a certain behavior with an environmental cue, and an intervention can kick start that association. If the HER makes people think about flipping off the light switch when they leave the living room, they will get used to turning off the light and gradually begin to do so every time they leave the room, without even thinking about it.
- Changing how or what people think. When people change their beliefs, interpretations, or perceptions of themselves, they often change their behavior to match. For example, if the HER makes someone identify as an energy efficient person, she may be more likely to pay attention to how much water she is using in the shower. The HER may also change how people think of environmental cues, for example, by making them associate a warm house in summertime with being energy efficient rather than with being slightly uncomfortable.
- Changing future costs. Some desired behaviors “are costly to perform,” the researchers point out, so reducing future costs can be an incentive for long-term change. HERs might make people more likely to buy energy-efficient appliances, which automatically reduce future costs.
- Harnessing external reinforcement. Well-designed interventions can create a cascade effect, in which performing the desired behavior elicits reactions that reinforce the behavior and make it more likely to continue. This can take the form of policies like tax incentives and rebates, or social reinforcement, as when friends and family praise homeowners for being more energy efficient or give them advice about further reducing consumption.
One of the intriguing implications of these pathways is that successful interventions like OPOWER’s can achieve long-term impact “for reasons that are entirely different than those that made the initial intervention successful,” write Frey and Rogers. The researchers offer a number of specific recommendations for policymakers who create or fund interventions, but the overall message is this: just as people need to make behavior changes to improve their lives and society, policymakers need to incorporate design changes to make interventions achieve long-term impact.