The article explores the complex dynamics of social norm change and the impact of different intervention strategies on social welfare in heterogeneous populations. The authors develop and analyze two models to examine the relationship between behavior change and social welfare, highlighting that the effectiveness of interventions can vary significantly depending on the population's heterogeneity and the specific intervention targets. In their models, the population is assumed to have heterogeneous preferences, which can lead to multiple equilibria. The social planner aims to shift the population from a harmful equilibrium to a beneficial one through an intervention. The key question is whether targeting the most amenable or resistant segment of the population is more effective in terms of social welfare. The authors find that in certain scenarios, targeting the most amenable segment can lead to higher social welfare even if it results in chronic miscoordination and less behavior change. This is because the most resistant individuals, who are not targeted, maintain their pre-existing preferences and tolerate frequent miscoordination, which can compensate for the costs of miscoordination. In contrast, targeting the most resistant segment can lead to genuine norm change but may harm social welfare if it does not align with the preferences of the most resistant individuals. The article concludes that ordinary forms of heterogeneity complicate applied cultural evolution, weakening the link between the size of an intervention and behavior change, and the link between behavior change and societal well-being. The findings have implications for policy makers and social planners who aim to engineer cultural change, emphasizing the need to consider the specific characteristics of the population and the potential consequences of different intervention strategies.The article explores the complex dynamics of social norm change and the impact of different intervention strategies on social welfare in heterogeneous populations. The authors develop and analyze two models to examine the relationship between behavior change and social welfare, highlighting that the effectiveness of interventions can vary significantly depending on the population's heterogeneity and the specific intervention targets. In their models, the population is assumed to have heterogeneous preferences, which can lead to multiple equilibria. The social planner aims to shift the population from a harmful equilibrium to a beneficial one through an intervention. The key question is whether targeting the most amenable or resistant segment of the population is more effective in terms of social welfare. The authors find that in certain scenarios, targeting the most amenable segment can lead to higher social welfare even if it results in chronic miscoordination and less behavior change. This is because the most resistant individuals, who are not targeted, maintain their pre-existing preferences and tolerate frequent miscoordination, which can compensate for the costs of miscoordination. In contrast, targeting the most resistant segment can lead to genuine norm change but may harm social welfare if it does not align with the preferences of the most resistant individuals. The article concludes that ordinary forms of heterogeneity complicate applied cultural evolution, weakening the link between the size of an intervention and behavior change, and the link between behavior change and societal well-being. The findings have implications for policy makers and social planners who aim to engineer cultural change, emphasizing the need to consider the specific characteristics of the population and the potential consequences of different intervention strategies.