Meta-analysis finds that environmental interventions significantly increase children's pro-environmental behaviors, especially for younger childrenPro-environmental behaviors (PEBs) are defined as actions that benefit the environment, or at least minimize harm to the environment to the greatest extent possible. With the growing urgency and intensity of environmental problems, supporting children’s development of environmental responsibility is critical. This systematic review and meta-analysis synthesized findings across the existing body of research on the interventions that aim to increase PEBs in children. While other reviews have focused on PEBs, the current study is unique in its concentration solely on the behaviors of children in response to environmental education interventions.
A systematic search of the literature was conducted to identify research on the effectiveness of interventions aiming to develop PEBs in children under the age of 18. Only peer-reviewed, published studies of pro-environmental interventions involving an experimental design that compared treatment and control groups through a quantitative assessment of PEBs were considered for inclusion in the review and meta-analysis. No limitations were placed on study language or publication date. Studies reporting household-level PEBs or involving adults were excluded from the review. The search resulted in 65 articles which were published in English between 1975 and 2020 and involved a total of 21,615 children. The studies involved various types of interventions, including environmental education interventions, interventions based on social influence mechanisms (such as social norms or role modelling), additive processes interventions (such as environmental education combined with social comparison) and eco-schools. The studies assessed children’s engagement in PEBs through either self-report measures, field observations, or laboratory observations. Studies using self-reports asked participants to report their PEBs by completing questionnaires. Studies employing field observations assessed PEBs through informant reports (such as parents), trained observers, or device measurement. Studies incorporating laboratory observations engaged participants in situations where their actual PEBs could be directly observed.
Across studies, meta-analysis of 76 independent samples found that overall, environmental interventions had a significant, medium-size effect on children’s PEBs. Separate analyses were conducted for potential moderators of the data, including age, gender, type of intervention, type of PEB assessment measure, intervention setting, and children’s passive or active involvement. Age was a significant predictor of intervention effectiveness, with studies of older children demonstrating smaller effect sizes than studies with younger children. This finding indicates that environmental interventions may be most effective for younger children. Results did not vary by the percentage of female participants, suggesting that there were no differences in intervention effectiveness associated with gender. The most common intervention type was environmental education (58%), followed by interventions based on social influence (20%), additive processes (13%) and eco-schools (9%). Each intervention group demonstrated significant gains in PEBs. The effectiveness of interventions employing environmental education, social influence, and additive processes were associated with medium effect sizes, while eco-schools yielded a small effect. As for PEB assessment measures, the majority of studies utilized self-reports (76%), followed by field observations (17%) and laboratory observations (7%). Larger effect sizes were associated with behavioral measures (field and laboratory observations combined) than self-report measures. No significant differences were detected between interventions that took place indoors and outdoors, suggesting that intervention setting was not a driver of effectiveness. On the other hand, interventions that actively engaged participants demonstrated a medium effect size on PEBs, while passive engagement yielded a small effect size. Another important finding was that validated instruments were only used in 20% of studies that relied on self-reports; the far majority (80%) utilized less reliable adapted or improvised instruments.
Compared to studies of adults, research on children’s PEBs is sparse and only 13 studies measured actual, not self-reported, PEBs. Despite these limitations, this meta-analysis revealed that pro-environmental interventions significantly increase PEBs among children across different types of interventions. PEBs were effectively promoted through group interventions that involved cooperative learning, exploring social norms, and the development of collective efficacy. The influence of children’s age on intervention effectiveness is consistent with prior research and suggests that “interventions can produce changes in PEBs more easily in younger than in older children.” Surprisingly, intervention effectiveness was greater when PEBs were assessed through behavioral measures rather than self-reports. The researchers also offer a future research agenda to strengthen understanding of how to best support children’s development of PEBs.
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