Causal role of environmental identity: A meta-analysis

Environmental identity is a multi-faceted construct that potentially comprises different identity constructs related to non-human environments and environmental protection. Environmental identity has become an important construct that has been hypothesized to be a causal factor of pro-environmental behavior. Yet, evidence of the causal role of environmental identity provided in individual studies is mixed, and meta-analytical evidence is largely missing. The current meta-analysis aims to summarize evidence from experimental studies (193 effect sizes from 47 papers, total N = 31,693) concerning the effect of environmental identity manipulation on outcome variables (pro-environmental behavior, intention, and attitude) and the effectiveness of such identity manipulation. We found that identity manipulation had a very small effect on environmental self-identity ( d = 0.13-0.15), and also a very small effect on outcome variables (pro-environmental behavior, intention, and attitude, d = 0.09-0.12), whereas there was a moderately strong association between environmental self-identity and outcome variables ( d = 0.72-0.81 equivalent to r = .34-.38). The already small effect of identity manipulation on outcome variables was likely inflated due to publication bias. These results are generally consistent with the notion of the causal effect of environmental identity on pro-environmental behavior, intention, and attitude. However, small manipulation effects and the presence of publication bias still warrant caution when interpreting the effect of identity on pro-environmental behavior, intention, and attitude as causal. Our results also reveal the difficulty of experimentally manipulating environmental identity. This may attest to the relative stability of this construct and imply that it may be difficult to use it as leverage for pro-environmental behavior in behavioral interventions.