Causal Role of Environmental Identity: A Meta-Analysis

Environmental identity has become an important construct and is hypothesized to be a causal factor of pro-environmental behavior. Existing meta-analyses and reviews of environmental identity literature did not specifically focus on the causal evidence of the effect of identity manipulation on pro-environmental behavior. The current meta-analysis summarizes causal evidence from experimental studies (120 effects sizes, total N = 15,228) that manipulated environmental identity and measured effects on outcome variables (pro-environmental behavior, intention, and attitude). We found that identity manipulation had a very small (d = 0.12) but statistically significant effect on outcome variables. However, the most common identity manipulation using the behavioral recall procedure had a smaller effect (d = 0.07) that did not reach statistical significance. The outcome or treatment type did not moderate the effect size. We also found a small effect of identity manipulation on identity constructs but a moderate to strong association between outcome variables and environmental identity. These results suggest that the evidence of the causal effect of identity on pro-environmental behavior and other outcome variables is very weak and partly or completely spurious. Future studies should focus on validating existing procedures for the manipulation of environmental identity and on developing alternative procedures.